A |
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Acceleration |
Acceleration is what occurs when the car moves forward from a stop
or from a slower speed to a higher speed. |
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Accelerator Pedal |
A
foot operated device which, directly or indirectly, controls the
flow of fuel and/or air to the engine, controlling engine rpm. Also
called the gas pedal. See Throttle. |
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Accelerator pump |
Accelerator pumps are found in cars equipped with carburetors. When
you accelerate, the accelerator pump delivers extra fuel through the
accelerator pump circuit to allow the engine to deliver more power. |
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Accessory |
Refers to a power-operated feature on a car. For instance, power
windows and power locks would be considered accessories. |
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Accumulator |
A
container in the air conditioning system used to remove moisture or
water. This helps to extend a/c compressor and other component life. |
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Actuator |
An
electrical mechanism for moving or controlling something indirectly
instead of by hand, such as a door lock. Output device the PCM
controls such as solenoids, relays, fuel injectors and stepper
motors. |
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Air Conditioning |
An
Original Equipment or Aftermarket accessory system that cools and
dries the incoming passenger compartment air. Aka: a/c |
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Air filter |
This device filters the air that goes into your engine. Without an
air filter, harmful particles would enter your car's engine and
cause internal wear and damage. |
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Air pump |
Many emissions systems include an air pump, which pumps fresh air
into a vehicle's exhaust to help complete the combustion process and
reduce emissions. |
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Airbag |
A
safety device, consisting of impact sensors, computer, a detonation
device and air bag, that protects the driver (and in some cases, the
passenger) in a crash by inflating a cushion hidden in the steering
wheel and dashboard. |
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Alignment |
Alignment is when all your wheels are pointing in exactly the right
direction. If one wheel is off by even one or two degrees, it is
considered out of alignment. When a vehicle is out of alignment,
excessive tire, steering system and suspension system wear may be
the end result. |
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All-wheel drive (AWD) |
An
all-wheel drive system has differentials which split the engine's
power to the four wheels according to which have the most traction. |
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Alternator |
An
alternator is an engine-belt driven device that converts mechanical
energy into electrical energy. The electrical output keeps your
battery charged and operates your vehicle's electrical system. |
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Anti-lock braking system (ABS) |
ABS uses a series of sensors, a computer and a high-pressure
hydraulic pump to prevent your brakes from locking up during sudden
stops on slippery surfaces. |
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Anti-roll bar |
The anti-roll bar is a suspension system component that helps a
vehicle to stay flat and not lean excessively when cornering. Also
called a sway bar or stabilizer bar. |
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Anti-theft code (radio) |
Many modern radios have special anti-theft circuitry that prevents
them from operating after being disconnected from a power source.
For these types of radios, it is necessary to enter a
factory-supplied code to get the radio to work again. |
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Antifreeze |
The fluid mixed with water that is put into your vehicle's radiator.
Antifreeze is traditionally green in color; however, newer long-life
antifreezes may be red or orange. Please refer to your vehicle's
owner's manual for the proper antifreeze for your vehicle. |
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Automatic choke |
Automatic chokes use either a heat- or computer-controlled element
to turn on and off automatically as needed. |
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Automatic temperature control |
A
computerized system that automatically maintains a selected
temperature for your car's interior. Also called climate control. |
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Automatic transmission |
Automatic transmissions have hydraulically operated gear sets, which
require no gear shifting or clutching by the driver. |
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Axial |
Referring to a type of air conditioning compressor that compresses
the R-12 refrigerant in a horizontal cylinder and piston compressor.
Compare to Radial. (Remember, Axial is LONG like an axle; Radial is
SHORT like a radial tire.) |
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Axle |
The shaft around which the wheels rotate. |
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B |
back to top |
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Balance Tube |
A
tube or pipe connecting the exhaust head pipes in a dual exhaust
system. This balance tube acts like a pressure equalizer enabling
both exhaust pipes to flow at the same pressure. |
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Balancing (tire) |
The process of making sure a tire will not cause vibration when
driving. By using a computerized machine, a technician can locate a
non-balanced tire and balance it by attaching weights on the wheel
rim to even out the tire's balance. |
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Ball joint |
A
joint between two parts that allows movement in any direction by the
two parts. Ball joints are most often found in a vehicle's
suspension and steering systems. |
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Barrel (carburetor) |
A
barrel is a venturi in a carburetor where air and fuel are mixed,
then taken into the intake manifold and then to a cylinder.
Carburetors usually have from one to four barrels, depending on the
engine application. |
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Battery |
An
electrical storage container designed to produce DC voltage by means
of an electrochemical reaction. This reaction occurs in the
container between the lead plates and sulfuric acid. Voltage is
supplied to the starting, ignition and other electrical systems. |
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Bearings |
Bearings are used to prevent wear when two moving parts are placed
very close to each other. |
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Bleeding |
Bleeding removes fluid from a system, such as a brake or clutch
system. When a technician bleeds a brake system, the old fluid is
completely removed and replaced with new fluid. |
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Blower Motor |
An
electric motor with a fan designed to supply a current of air at a
moderate pressure. A blower usually consists of a fan assembly, a
motor, and a suitable case. The blower case is usually designed as
part of the heating/air conditioning system. |
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Blueprinting |
The procedure of dismantling an engine, measuring, machining
components, and reassembling it to the minimum factory tolerances.
This procedure usually will provide more power and efficiency |
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Body |
The assemblage of components, including windows, doors, seats, etc.,
that provide enclosures for passengers and/or cargo in a motor
vehicle. |
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Body Control Module (BCM) |
A
device powered by the main vehicle computer that takes input from
various sensors to control components such as the air bag, headlight
sentinel and door chime. |
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Brake |
A
device, such as the disc or drum brake, for retarding motion. This
is usually created by means of friction caused by a clamping force
from a stationary caliper or shoe, against a rotating rotor or drum. |
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Brake booster |
A
device that uses engine vacuum or hydraulic pressure to multiply or
boost the pedal effort of the driver while braking, thus adding more
hydraulic pressure to the brakes for added stopping power. |
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Brake caliper |
A
c-shaped device used with disc brakes. When a driver presses on the
brake pedal, the caliper piston squeezes the brake pads against the
rotor and causes the car to slow down or stop. |
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Brake drums |
Brake drums are drum-shaped components which contain internal brake
shoes, which expand and press against the drum, when the driver
presses on the brake pedal, slowing or stopping the car. |
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Brake fluid |
A
special type of hydraulic fluid designed specifically for brakes.
Brake fluid transfers the motion of a driver stepping on a brake
pedal directly to operate a brake caliper or wheel cylinder. |
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Brake lines |
Metal tubing and rubber hoses which connects each brake caliper or
wheel cylinder to the brake master cylinder. |
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Brake master cylinder |
As
the main component of a braking system, the brake master cylinder
takes the pressure applied to the brake pedal by the driver and
distributes it evenly to all four brakes on a car. |
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Brake pads |
Brake pads are used specifically with disc brake systems. The pads
fit inside the calipers, and create friction and stopping power when
pressed against the brake rotor. When you have your disc brakes
replaced, it is often just the pads that are being replaced. |
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Brake pedal |
The pedal to the left of the accelerator pedal that controls a car's
brakes. When you step on the brake pedal, the car slows down or
stops. |
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Brake rotors (discs) |
Brake rotors, or discs, are fitted to most modern cars. They are
flat, circular plates that rotate with the wheel when you drive.
When you step on the brake, the brake calipers squeeze the brake
discs, slowing or stopping the car. |
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Brake shoes |
Brake shoes are used specifically with drum brake systems. Brake
shoes fit inside the brake drum, and are pressed against the drum by
a wheel cylinder when the brakes are applied, thus slowing or
stopping the car. |
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Braking system |
The braking system in a modern car consists of the brake pedal, a
power brake booster, brake master cylinder, brake lines, brake
fluid, brake rotors (including calipers and pads), and, for some
vehicles, brake drums (including wheel cylinders and brake shoes).
In addition, all vehicles have a parking/emergency brake. Taken
together, these components operate in sync to slow or stop your car.
They operate like this: when you press on the brake pedal, the
pressure you apply is multiplied by the brake booster. It is then
distributed by the brake master cylinder and sent via the brake
fluid through the brake lines to each individual wheel. When it
arrives at a wheel, this pressure causes, for instance, the caliper
(in a vehicle with disc brakes) to close, which then causes the pads
to come in contact with the brake rotor. The resulting friction
causes the car to slow down and eventually stop. Should this system
fail, then the emergency brake may be used as a backup to stop your
vehicle. |
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Burning oil (engine) |
Oil burning occurs when one or more internal engine components fail,
thus allowing oil into the engine's combustion chamber. There, the
oil is burned along with the air/fuel mixture. |
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Bushing |
A
piece of rubber or plastic that fits in between two components.
Bushing protects the two components from excess wear and damage. |
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Bypass |
Providing a secondary path to relieve pressure in the primary
passage. One example would be a water pump or thermostat housing
bypass in the cooling system. |
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C |
back to top |
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Caliper |
The housing on disc brakes which holds the disc pads and straddles
the brake rotor. When hydraulically actuated, the pads press against
the rotor, or disc, to stop or slow the vehicle wheels. |
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Camber |
It's the adjustment of a wheels alignment where the top of the wheel
is moved inward or outward from vertical as viewed from the front of
the vehicle. Incorrect camber reduces tire life. |
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Camshaft |
A
camshaft, with phased cam lobes mounted on it, regulates the opening
and closing of the intake and exhaust valves. Driven by the
crankshaft via a timing chain or timing belt, a camshaft has a big
influence on engine power characteristics. |
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Canister |
An
evaporative emission canister contains activated charcoal which
absorbs fuel vapors and holds them until the vapors can be purged
into the engine when it is started. It is a component of the
emissions control system. |
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Capacitor |
An
electrical device for accumulating and holding a charge of
electricity. A capacitor is usually found in an electronic ignition
system. |
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Carb |
See Carburetor. |
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Carbon Dioxide |
A
heavy, colorless gas that results as a product of complete
combustion. It is considered a greenhouse gas. |
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Carbon Monoxide |
A
colorless, odorless gas that can be found as a product of incomplete
combustion. Breathing high concentrations can be dangerous. |
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Carburetor |
A
mechanism which mixes fuel with air in the proper proportions to
provide a desired power output from a spark-ignition internal
combustion engine. On production vehicles, carburetors have been
replaced by electronic fuel injection. |
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Carburetor jet |
A
fitting inside a carburetor that meters fuel into a metering circuit
where it is mixed with air in the venturi. |
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Caster |
An
alignment spec where an imaginary line through the ball joints
(steering axis) intersects a vertical line through the front wheel
center. Positive caster delivers directional stability and improved
steering feel. |
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Catalyst |
A
substance that can increase or decrease the rate of a chemical
reaction between substances without being physically consumed in the
process. A catalyst, which reduces engine emissions, is used in a
catalytic converter. |
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Catalytic converter |
An
in-line, exhaust system device, containing a catalyst, which reduces
engine exhaust emissions. Converters are located near the exhaust
manifolds or headers for maximum efficiency. |
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Charging system |
The system which maintains the electrical charge in your vehicle's
battery. The charging system consists of the alternator, voltage
regulator and battery. |
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Chassis |
The suspension, steering, and braking components of a vehicle.
Everything but the body, fenders, etc. |
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Choke |
A
device in a carburetor which shuts off airflow so that the engine
runs rich. This is necessary to start a cold engine. |
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Circuit |
A
complete electrical path, usually includes the electrical energy
source. May also be used with fluids or air. The headlights and
brake system are examples of an electrical and hydraulic circuit. |
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Cleaner (Air) |
A
housing holding a filter fitted in the intake system of parts
requiring clean air. An engine air cleaner filter removes
particulates before they can enter the intake system and cause
damage. |
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Clear-coat finish |
Many modern cars have a clear-coat finish. This is an extra, clear
layer of paint that goes on top of the last color coat of paint to
protect it from scratches, chips and other environmental damage. |
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Climate Control |
Describes temperature/ventilation environment in the passenger
compartment. Climate adjustments are made by adjusting the heater/
ventilation and A/C controls. Aka automatic temperature control. |
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Closed Loop (Engine) |
An
operating mode of the PCM enabling modification of pre-programmed
instructions based on a feedback system. By constant exhaust
sampling, a closed loop system allows pre-programmed engine
adjustments to occur while running in order to minimize exhaust
emissions. |
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Clutch |
A
mechanical device which uses mechanical, magnetic, or friction type
connections to facilitate engaging or disengaging two rotating
members. Examples: the friction clutch located between the engine
and manual transmission or the a/c clutch. |
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Clutch - cable-operated |
A
cable-operated clutch uses a metal cable between the clutch pedal
and clutch fork to control clutch engagement. |
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Clutch - hydraulic |
A
hydraulic clutch uses a hydraulic circuit between the clutch pedal
and clutch fork to control clutch engagement. |
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Clutch disc |
The friction material lined plate that delivers power from the
engine to the transmission. |
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Clutch pedal |
The pedal on manual transmission cars that operates the clutch. |
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Clutch throw-out bearing |
A
bearing that lets the clutch pressure plate and disc smoothly engage
and disengage with minimum wear. |
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Clutch-operated fan |
An
engine cooling fan that uses a heat-activated, viscous-fluid clutch
which turns the fan on and off as needed. |
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Code |
A
system of symbols (as letters, numbers, or words) used to represent
the meaning of information. An engine trouble code shows where a
vehicle system or component failure may be occurring. |
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Coil (Ignition) |
A
device consisting of fine wire windings around an iron core, which
is designed to step up battery voltage. The high voltage created
(35,000 volts or more) is delivered to the spark plug so ignition
can occur. |
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Coil Spring |
A
spiral-wound steel wire coil, of various wire diameter thicknesses
and coil stack heights, used to suspend a vehicle. Can be used in
cars and trucks, both front and rear, depending on the application. |
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Combustion |
The process by which the air/fuel mixture burns within an engine to
create power. |
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Combustion chamber |
The area in the cylinder head where air/fuel is ignited to create
power. |
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Comprehensive insurance coverage |
Comprehensive coverage includes protection against theft and
accident damage, regardless of fault. |
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Compression gauge |
A
special gauge used by technicians to measure how much pressure a
cylinder can create. |
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Compression test |
A
test to see how much pressure a cylinder can create. |
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Computer (PCM) |
Many modern cars have a central computer called an engine control
unit (ECU) or power train control module (PCM). This controls the
car's fuel and ignition systems by taking information from various
sensors to determine how to run the engine with the most efficiency
and power. |
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Constant Velocity Joint |
A
coupling that allows a shaft to turn continuously at various angles
when coupled with another shaft. Usually associated with front-wheel
or all-wheel drive vehicles. |
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Converter (Torque) |
A
fluid coupling device which multiplies torque between an engine and
automatic transmission/transaxle. When a vehicle is stopped, a
converter allows enough fluid slippage, so the engine can idle
without stalling. |
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Coolant |
A
fluid used in the radiator for heat transfer. Mixed with water,
coolants usually contain rust inhibiting additives and provide
antifreeze protection. Some new vehicle coolants are designed to
last 100,000 miles. Please refer to your owner's manual for the
proper antifreeze for your vehicle. |
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Coolant reservoir |
Many cars have a clear plastic reservoir that allows the owner to
see the level of their vehicle's coolant. Check your owner's manual
to find the coolant reservoir on your vehicle. |
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Cooler |
A
heat exchanger that reduces the temperature of the cooling medium.
Two examples would be a engine radiator or oil cooler. |
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Cooling system |
The system of components that keeps your engine at the correct
operating temperature. The cooling system includes the radiator,
radiator cap, coolant reservoir, cooling fan, water pump,
thermostat, hoses, heater core, heater valve, and antifreeze. |
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Core (Price/Charge) |
A
payment that is credited back to the buyer after they have returned
a rebuildable Core unit to the retailer. A rebuilt alternator
purchase would have a core charge and would require returning the
old one to receive the credit. |
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Cracked paint |
Cracked paint occurs when a paint is so damaged, the surface
actually develops cracks. These cracks may spread in a spider web
fashion across the surface of the paint. Cracked paint is
unrestorable, and must often be completely removed when a car is
repainted. |
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Crankshaft |
The engine component which converts piston reciprocating (up and
down) motion into rotary motion at the flywheel or flexplate.
Connected to the clutch or torque converter, engine torque is
delivered to the drivetrain to move the vehicle. |
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Crazed paint |
Crazed paint occurs when paint is so damaged, the surface actually
develops hairline cracks. These cracks may spread in a spider web
fashion across the surface of the paint. Crazed paint is
unrestorable, and sometimes has to be completely removed when a car
is repainted. |
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Cruising |
Cruising is a driving style whereby the driver maintains a set speed
with very little fluctuation. |
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| CV
joints |
CV
(constant velocity) joints are part of a car's driveline. They allow
a wheel to rotate freely in any direction while still receiving
power from the axle. |
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Cylinder |
Cylinders are the large round holes in the engine block in which
combustion occurs. This combustion forces the piston down and turns
the crankshaft. |
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Cylinder Head |
A
removable part located on the top of the cylinder block; it usually
contains valvetrain components and combustion chambers. For an
overhead cam engine, it contains the camshafts as well. A head is an
important influence in determining an engines overall power and
efficiency. |
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D |
back to top |
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Data |
General term for information, usually represented by numbers,
letters and symbols. A gas gauge is an instrument that provides data
to the driver. |
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Defroster |
A
setting of your car's heating controls that lets you easily remove
frost and fog from your vehicle's windows. |
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Diagnostics |
The process of identifying the cause or nature of a condition or
situation. Most cars have computer diagnostic systems that help the
technician to determine corrective repairs. |
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Diesel engine |
A
type of engine that uses heat caused by engine compression rather
than spark plugs to ignite its fuel mixture. Diesels are often more
economical than gasoline engines, however they create extra noise
and vibration. |
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Dieseling |
The continued running of a spark-ignited engine after the ignition
is turned off. There are two basic causes of dieseling: surface
ignition, where combustion chamber surfaces remain hot enough to
ignite fuel after the spark is terminated; compression ignition,
where the conditions of temperature, pressure, fuel composition and
engine idle speed allow ignition to continue. |
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Differential |
A
component of the drivetrain with an arrangement of gears designed to
permit the division of power between two shafts. A differential also
lets two wheels on the same axle rotate at different speeds. With
out one, cars wouldn't be able to take sharp turns. Differentials
are located in a drive axle housing. |
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Distributor |
Part of the ignition system, its a mechanical device designed to
direct high voltage electricity from the coil to the spark plugs,
via the spark plug wires. Rotating the distributor permits
adjustment of an engine's initial ignition timing. |
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Distributor cap |
The distributor cap contains the terminals that the spark plug wires
plug into. When the distributor sends power to a spark plug, it goes
to the cap first and then to the spark plug wire and to the spark
plug. |
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Distributor rotor |
The rotor spins around inside the distributor. As it turns, it comes
close to the terminals for each spark plug on the distributor cap.
When this happens, it sends current to the spark plug, which then
ignites the air/fuel mixture in the cylinder at exactly the right
time. |
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Double overhead cam (DOHC) |
A
DOHC engine has two camshafts in the cylinder head - one for the
exhaust valves, and one for the intake valves. This allows greater
efficiency and greater power. |
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Downshifting |
The process of going from a higher gear (for instance, fourth gear)
to a lower gear (for instance, second gear) with a manual or
automatic transmission. |
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Drive belt |
Also called a fan belt or serpentine belt, drive belts are used to
drive the engine's accessories, such as the alternator, power
steering pump, and air conditioning compressor. A serpentine belt is
a wide single drive belt that drives several the engine's
accessories at once. |
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Driveline |
The system of components that connects the transmission to the
wheels. The driveline consists of axles, differentials, constant
velocity (CV) or universal joints, and a driveshaft. |
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Driver |
A
switched electronic device housed in a computer that controls output
state. For example, a driver controls how long a fuel injector
remains open. |
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Driveshaft |
The shaft connecting the transmission output shaft to the
differential pinion shaft. It transmits power from the transmission
to the differential. It is found primarily on rear-drive vehicles.
There is usually a universal joint on either end. |
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E |
back to top |
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Early Fuel Evaporation |
Used on carburetor-equipped engines only, a system where heat is
used to help increase early fuel evaporation of the cold-start
air/fuel mixture to achieve more efficient combustion and lower
emissions. GM used an electric grid system. |
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Electric cooling fans |
Electric cooling fans are part of many cars' cooling systems. They
use a heat activated switch to turn on and off as needed to help
keep your engine cool. |
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Electric motor |
Any device that converts Electromagnetic force to motion, or
vice-versa. Electric motors are often used in accessories such as
power windows or power seats to provide movement with minimal effort
by the user. |
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Emergency brake |
Also called the parking brake. A braking system which is independent
of the main hydraulic system. It can be used to slow or stop the
vehicle if the primary brakes fail, or to hold the vehicle
stationary though the brake pedal is not depressed. It usually
consists of a foot pedal or hand lever that actuates either front or
rear brakes mechanically through a series of cables and linkages. |
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Emissions |
Emissions are the byproducts of combustion. After combustion is
complete, water, gases, and carbon are released through the car's
exhaust system as emissions. |
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Emissions equipment |
Emissions equipment is equipment required by the government to keep
a car's exhaust emissions to a minimum. Emissions equipment includes
catalytic converter, air pump, and oxygen sensor. |
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Engine |
A
machine designed to convert thermal energy into mechanical energy to
produce force or motion. Connected to a drivetrain, an engine's
mechanical energy, or torque, moves a vehicle. An engine can run by
using gas, diesel fuel, steam or other fuel sources. |
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Engine accessory |
An
engine accessory is a peripheral piece of equipment that runs
directly off of the engine's power to supply energy or a fluid to
another part of the car. Engine accessories include the alternator,
power steering pump, air pump, air conditioning compressor, as well
as many others. |
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Engine block |
The engine block is where the cylinders and pistons reside. The
block is the strongest part of the engine and withstands tremendous
pressures while the engine is operating. |
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Engine mounts |
Engine mounts are often made of metal and rubber. Engine mounts help
support the engine, and also help to prevent engine vibrations from
shaking the entire car. |
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Engine temperature sender |
The engine temperature switch and sending unit measure the
temperature of the engine's coolant. They send this information to
the engine temperature warning light and engine temperature gauge,
respectively. Compare to coolant temperature sensor (CTS) which
transmits the coolant temperature to the computer, and the radiator
fan switch which engages the radiator's cooling fan. |
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Evaporative Emissions Control |
A
system which filters evaporating fuel fumes from the vehicle's fuel
system and routes them to the engines intake to be burned. |
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Exhaust |
Gaseous by-products of combustion emitted from an engine. Exhaust
flows from the engine, through the muffler and exits from the
exhaust system. |
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Exhaust Gas Recirculation |
An
engine system where a small portion of exhaust gases are recycled
into the combustion chamber. This lowers combustion temperatures and
reduces oxides of nitrogen emissions. The EGR system is important
for a smooth performing engine. |
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Exhaust hanger |
Exhaust hangers keep the exhaust system in place, while also
preventing excess vibration and noise from reaching the passengers. |
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Exhaust manifold |
The exhaust manifold carries the exhaust from the cylinder head to
the exhaust system. |
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Exhaust system |
The exhaust system carries exhaust away from the engine and away
from the car. The exhaust system includes the exhaust manifold, the
catalytic converter, the muffler, and the tailpipe. |
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F |
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Fan |
Designed to supply air flow as the fan blades rotate, a fan can be
driven by either a motor or belt. |
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Fan belt |
Also called a drive belt or serpentine belt. Fan belts are used to
drive the engine's accessories, such as the alternator, power
steering pump, or air conditioning compressor. A serpentine belt is
a wide single drive belt that drives multiple engine accessories. |
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Fan clutch |
A
viscous-fluid clutch that controls how fast an engine fan rotates to
help cool an engine. |
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Fan motor |
An
electric motor which drives a fan to direct air, through a radiator
or car's interior, for example. |
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Feedback Carburetor |
A
computer-controlled carburetor that adjusts the air/fuel mixture
according to input from various sensors, via a mixture-control
solenoid. The solenoid's adjustment helps maintain the correct
air/fuel ratio and minimizes exhaust emissions. |
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Feeler Gauge |
An
instrument used to measure the distance between two metal contacts.
A feeler gauge could be use to measure spark plug gap, point gap or
valve clearance. |
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Fiberglass matting and resin |
These materials are often used to fill in large rust holes where
filler would be unable to work, and where welding in new metal would
be difficult. |
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Final Drive Ratio |
The ratio between the pinion and ring gear in the drive
differential. A numerically high ratio enhances vehicle acceleration
and pulling ability, while a numerically low ratio enhances highway
cruising and fuel economy. |
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Flexplate |
Secured to the end of the crankshaft, it has three functions; the
ring gear for the starter on the outside diameter; helps to balance
out engine vibrations; a connection between the transmission torque
converter and the engine allowing flexing. Compare to flywheel for
manual transmission. |
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Flushing |
Flushing is a means of entirely replacing the fluid in a given
system. For instance, when a technician flushes a cooling system,
all the old coolant is removed and completely replaced with new. |
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Flywheel |
Secured to the end of the crankshaft, it has three functions; the
ring gear for the starter on the outside diameter; helps to balance
out engine vibrations; a connection between the transmission clutch
and the engine. Compare to flexplate for automatic transmission. |
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Four-wheel drive (4WD) |
A
drive system in which both the front and rear wheels are connected
through the driveshaft and axles to the transmission, usually via a
transfer case. A 4WD system can be full time or part time. Sometimes
called 4x4 (four by four). |
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Front-wheel drive (FWD) |
A
front-wheel drive vehicle sends its power from the engine to the
front wheels of the car. |
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Fuel |
Any combustible substance burned to provide heat or power. While
gasoline is the most common, other fuels include diesel, ethanol and
natural gas. |
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Fuel filter |
A
car's fuel filter removes debris and contaminants from fuel before
it reaches the carburetor or fuel injection system. |
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Fuel injection |
Fuel injection is a system by which fuel is directly sprayed into
the intake manifold or intake port at high pressure. Fuel injection
is often controlled by a computer, allowing precise monitoring of
efficiency and performance by the car's computer. |
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Fuel injector |
A
device for delivering metered, pressurized fuel to the intake system
or individual cylinders. An injector sprays fuel, which helps
atomization for a more dense mixture, when combined with incoming
air. |
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Fuel pump |
The fuel pump moves gas from the gas tank and delivers it to the
fuel injection system or carburetor. |
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Fuel starvation |
Fuel starvation occurs when fuel, for one reason or another, is
prevented from reaching the carburetor or fuel injectors. |
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Fuel system |
The fuel system is the system by which fuel is stored and delivered
to each cylinder. The fuel system includes the fuel tank, fuel tank
level sending unit, the fuel pump, the fuel filter, and fuel lines.
For carbureted cars, the fuel system also includes the carburetor.
For fuel injected cars, the fuel system also includes injectors,
fuel pressure regulator and often a main computer. |
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Fuel tank level sending unit |
This unit measures the amount of gas in the fuel tank and sends that
information to the vehicle's gas gauge and, if equipped, a low gas
level warning light. |
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Fuses |
A
device designed to open and protect equipment or a circuit from
being destroyed when the circuit is subjected to a power overload.
This is a non-reversible action and there are 3 main types of fuses;
glass, ceramic and spade. |
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G |
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G-Force |
Unit of measurement used to describe lateral acceleration generated
while the vehicle is driven in a steady state turn on a skid pad
circle. An average sedan generates 0.60 G of lateral acceleration.
Measured in "gravities", one G equals the earth's gravity at sea
level. |
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Gas - grade |
This is a general term that refers to a gasoline's general quality -
for instance, its octane rating and package of additives. The two
common terms for gas grades are "regular" for low-grade gas, and
"premium" for high-grade gas. |
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Gasket |
A
material usually made of rubber, cork, metal, paper or a combination
thereof that is placed between two surfaces to ensure proper sealing
against the passage of air, liquid or vapors. Valve cover gaskets
are one example of a popular gasket. |
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Gauge |
A
gauge is a type of instrument that measures or displays levels of a
certain system. For instance, the gas gauge in a vehicle measures
the fuel level, while the temperature gauge measures the engine
temperature. |
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Gear selector |
The gear selector is the lever that lets you select a certain gear
with an automatic transmission. In modern cars, the gear selector is
often connected to the brake pedal, so that you can only shift into
drive or reverse when your foot is on the brake. |
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Gear synchronizers |
Gear synchronizers allow you to upshift and downshift a manual
transmission without grinding gears. They do this by synchronizing,
or matching, the speed of the engine and the speed of the gear you
are selecting. If your car didn't have gear synchronizers (also
known as synchromesh), you would either have to match the engine
speed to the gear speed (known as double-clutching) or else grind
your gears every time you shifted. See also "synchromesh". |
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Gearshift lever |
The gearshift lever is the lever that allows you select the
different gears of a transmission. |
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Gearshift linkage |
This is a series of rods and/or cables that connect the gearshift
lever or gear selector to the transmission. |
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Generator |
A
generator is like an alternator in that it generates electrical
current to both keep the battery charged and supply electricity for
a vehicle's electric system. It differs from an alternator in that a
generator generates direct current (DC) where an alternator
generates alternating current (AC). |
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Glass Pack |
A
muffler design that contains fiberglass packing around a perforated
internal pipe (straight through) which slightly deadens exhaust
noise. Usually louder than a conventional replacement muffler. |
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Glazing (belts) |
Glazing is a shiny coating on the inside surface of a fan, or
serpentine belt. Glazing occurs when the belt slips repeatedly at a
high speed. It is a sign that the belt needs replacement. |
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Glow Plug |
A
combustion chamber heat generating device to aid starting diesel
engines. When the glow plug heats the combustion chamber to the
proper temperature, the ignition key can be turned to engage the
starter. |
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Governor |
An
electronic or mechanical device designed to limit engine speed.
Large diesel engines usually are equipped with governors. |
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Ground |
An
electrical conductor used as a common return for completing an
electric circuit(s). Car batteries contain a ground terminal,
usually the negative terminal. |
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H |
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Halfshaft |
An
exposed axle driveshaft usually having a CV (constant velocity)
joint on either end, being driven from a differential. Also called a
CV axle. |
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Hazard relay |
The hazard relay controls the flashing of the hazard warning lights. |
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Head gasket |
The head gasket seals the cylinder head to the engine block. It is
subject to tremendous pressures, and often fails if and when an
engine overheats. |
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Headers |
Constructed from steel tubing, headers provide a smooth and
efficient exhaust flow path from the exhaust port to the exhaust
system. Headers are frequently used in performance engine
applications and are generally less restrictive than the stock
exhaust manifold, resulting in increased power. |
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Heater core |
The heater core is a miniature radiator that sits in the dashboard
area. When the heater is turned on, it opens the heater valve which
lets hot coolant into the heater core, which then warms the air
coming into the vehicle's interior. |
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Heater ducts |
The heater ducts are the passageways through which warmed air enters
the interior of the vehicle. |
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Heater fan |
The heater fan is the interior fan attached to a blower motor that
controls the speed of air being introduced into the interior. |
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Heater valve |
The heater valve is controlled by the interior heating controls.
When you turn on your vehicle's heater, the valve opens and allows
hot coolant to enter the heater core, which then warms the air
forced through the heater core by a blower motor, and the warmed air
then enters the vehicle's interior. |
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Heater/heating system |
The heating system warms the air brought into a vehicle's interior.
The heating system is connected to the cooling system and consists
primarily of the heater core, heater valve, and, if equipped, a
climate-control system. |
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Hex Wrench |
Also known as an Allen wrench, it is a hexagonal tool that fits and
operates fasteners with hexagonal openings. |
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Hoses (cooling system) |
The cooling system hoses allow coolant to circulate between the
radiator, engine, and heater. Over time, they deteriorate, and
should be checked annually for condition and possible damage. |
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Hub |
Hub is a generic term for a circular area where a component is
mounted. For instance, there are hubs for every wheel on your car. |
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HVAC |
Stands for Heating, Ventilation, Air Conditioning. These systems are
controlled by the car's climate control panel. |
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Hydraulic circuit |
The hydraulic circuit is a closed system of tubes and components
that contain hydraulic fluid. When pressure is applied at one end of
the hydraulic circuit, it travels through the tubes to the other
end. |
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Hydrocarbon |
An
organic compound containing various carbon and hydrogen molecules
linked together in fuel. Gasoline is a hydrocarbon fuel. If the fuel
is not burned efficiently in the cylinders, hydrocarbon molecules
are released into the atmosphere as pollutants. |
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I |
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Idle |
Running engine speed with vehicle at rest and accelerator or
throttle pedal not depressed. While waiting at a stop light, the
engine is at idle. |
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Idle circuit |
This is a special kind of circuit found in a carburetor that only
operates when the engine is at an idle. |
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Ignition |
Complete system used to step up battery voltage to a higher voltage
and deliver it to the spark plug to complete the combustion process.
When the key is turned on, the ignition system is energized. |
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Ignition Advance/Retard |
The advancing or retarding (in crank degrees) of ignition spark
relative to the piston location in the cylinder. Ignition timing
should be set to factory specifications. |
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Ignition condenser |
The condenser collects and stores excess electrical energy in an
older ignition system that has points. This prevents that extra
energy from jumping across the points when they first open and
close. |
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Ignition module |
Part of the ignition system which instructs the ignition coil to
send current to the distributor. |
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Ignition points |
Part of the ignition system which allows the ignition coil to send
current to the distributor in older vehicles. Ignition points do
this by opening and closing, which opens and closes the electric
circuit. Electronic ignition systems have made ignition points and
condensers obsolete. |
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Ignition switch |
This is the switch where you insert the key that starts the vehicle. |
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Ignition system |
The ignition system contains the components that supply spark to the
vehicle's spark plugs. These include the battery, the ignition coil,
the distributor (including the cap and rotor), the spark plug wires,
the ignition module, and the spark plugs themselves. Older cars also
have ignition points and an ignition condenser. |
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Injector (fuel) |
A
device for delivering metered, pressurized fuel to the intake system
or individual cylinders. A fuel injector sprays fuel, which helps
atomization for a more dense mixture, when combined with incoming
air. |
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Instrument |
An
instrument measures levels of a certain system and provides a visual
key for those levels. For instance, the gas gauge in your car
measures the fuel level, while the temperature gauge indicates the
engine temperature. |
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Intake Air |
Air used in combustion that flows through an air filter, throttle
valve and is distributed to each cylinder by the intake manifold. |
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Intake manifold |
The intake manifold is located between the vehicle's fuel system and
the cylinder head(s) to distribute the fuel/air mixture to
individual cylinders. |
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K |
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Knock (Engine) |
The sharp, metallic sound produced when two pressure, or flame
fronts collide in the combustion chamber. This could be the result
of incorrect ignition timing or the wrong grade (octane rating) of
gas. Higher octane fuel can eliminate knock due to its increased
resistance to cylinder pressure. |
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L |
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Lathe |
Device used to machine the outside and/or inside of a metal object
as it rotates. A brake lathe is used to smooth the exterior pad
surface of a brake rotor or the interior of a brake drum. |
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Leaf Spring |
A
thin, long, arched, steel spring that is attached between a vehicle
frame and axle to act as a suspension. More than one spring leaf are
often clamped together to achieve a desired load capacity or spring
rate. |
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Leakdown test |
A
leakdown test is used to find excessive wear in an engine. When a
technician performs a leakdown test on a vehicle, each cylinder is
tested to see how well it holds pressure. If a cylinder is unable to
hold pressure, your technician can pinpoint what component of the
cylinder (piston rings, valves, etc) has the problem that is causing
the pressure loss. |
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Liability insurance |
Liability insurance is coverage only for damage that you inflict on
other people or their possessions. It does not cover theft or damage
to your vehicle. |
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Limited-slip differential (LSD) |
An
LSD senses the slippage of each wheel and sends and redirects power
to the wheel with the most grip. Many high-performance vehicles have
LSDs. |
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Link (Electrical/Electronic) |
General term used to indicate a communication connection between two
data points. Mechanics use a link to retrieve trouble codes from a
vehicle's ECU in order facilitate repairs. |
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Linkage |
A
series of bars, levers, yokes, rods, or cables used in unison to
transmit motion from one unit to another. Transmission shift linkage
connects the shifter to the transmission and allows gear selections
to be made. |
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Loaded (caliper) |
A
disc brake caliper, which comes complete with all the installation
hardware such as emergency brake lever, spring, bracket and brake
pads. This speeds a caliper installation during replacement. |
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Lug nuts |
Lug nuts attach a car's wheel to its hub. Also known as wheel nuts. |
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M |
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MacPherson strut |
A
shock absorbing component in a front suspension system that is
mounted directly above the upper control arm. Many lightweight,
uni-body cars use this uncomplicated type of front suspension. |
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Main Bearings |
Soft metal alloy inserts, bonded to a steel back, used to allow the
crankshaft to ride on a cushion of oil formed between the crank
journal and bearing surface. Main bearings often last throughout the
life of the engine. |
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Manifold |
A
component designed to collect and/or distribute an engine's air
and/or fuel mixture, or exhaust. |
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Manual choke |
A
manual choke system has a cable that lets the driver control the
carburetor's choke operation. Most newer cars with carburetors have
automatic chokes instead of manual chokes. |
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Manual steering |
With a manual steering system, there is no power assist to the
driver. |
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Manual transmission |
A
manual transmission is a transmission with a clutch. In addition, it
is up to the driver to select gears. |
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Memory |
A
device in which data can be stored and retrieved when needed;
associated with a vehicle's computer system. |
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Mode |
One of several alternative conditions or methods of operating a
system, device or control module. If a vehicle has a 3-mode
electronic adjusting shock absorber system, the modes (or settings)
are usually soft, medium, or firm. |
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Module (Electrical/Electronic) |
A
self-contained group of electrical/electronic components, which is
designed as a single replaceable unit. An example of a module is the
one that operates the anti-lock braking system. |
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Muffler |
The muffler is a part of the exhaust system designed to reduce the
noise generated by a vehicle. |
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N |
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Neutral (gear) |
Neutral is actually not a gear. When your vehicle is in neutral, the
gearbox (transmission) and engine are completely disconnected. Thus,
your car is able to roll freely whether the engine is on or off. |
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O |
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Octane |
A
fuel octane rating measures a fuel's resistance to knocking or
pinging. The higher the octane rating, the better (and more
expensive) the fuel. |
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Odometer |
The odometer measures how many miles your vehicle has traveled. |
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Oil filter |
The oil filter removes most particles and contaminates from your
engine's oil to protect your engine's internal moving parts. |
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Oil pan |
The oil pan is where the oil in your engine is stored. |
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Oil pressure sensor |
The oil pressure sensor measures the pressure at which your engine's
oil is flowing. If the pressure becomes too high or too low, the oil
pressure sensor sends a signal to the vehicle's oil pressure warning
light located on the dashboard. If you see this light turn on, pull
over as soon as possible and shut off your engine. Check the oil
level of the engine by pulling out the dipstick. If the engine oil
level is low, add oil, restart the vehicle and see if the oil light
goes out. If the oil level is within parameters, or the oil light
remains on, have your car towed to a service facility to have the
problem checked by a technician. |
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Oil pump |
The oil pump takes oil from the oil pan and pressurizes it, allowing
it to travel throughout the engine and lubricate the engine's moving
parts. |
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Open Loop |
An
operating condition or mode in the vehicle's intake fuel system
controlled by the vehicle's PCM, based on pre-programmed
instructions, usually when an engine is in the cold start-up mode. |
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Output Shaft |
A
shaft that drives the next element in the power train, like the
front driveshaft yoke slipping over the output shaft of the
transmission, which drives the wheels. |
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Overboost (turbo) |
Overboost occurs when a turbo's wastegate does not release excess
intake pressure. This pressure instead enters the engine, causing
potentially significant damage to the engine. |
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Overdrive |
Overdrive is a transmission gear that allows the engine to turn at a
reduced rpm for a given road speed. |
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Overhead cam (OHC) |
An
overhead cam engine has its camshaft in the cylinder head, above the
valves and cylinders. This allows the camshaft to directly open the
valves without using pushrods. |
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Overhead valve (OHV) |
An
overhead valve engine has its camshaft in the engine block. It uses
lifters, pushrods and rocker arms to open and close the valves in
the cylinder head. |
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Overheating |
Overheating occurs when an engine reaches too high of an operating
temperature. Overheating may lead to potentially significant engine
damage. |
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Overinflation (tires) |
Overinflation occurs when a tire is inflated beyond the pressure
recommended by the manufacturer. Overinflating can lead to increased
tire wear and sudden tire failure. |
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Owner's manual |
The owner's manual is the booklet supplied with all cars when they
are sold new. It is usually placed in the glovebox. The owner's
manual contains information about the vehicle's equipment and
options, what kinds of fluids and lubricants to use, and how to
maintain your car. If you don't have an owner's manual, one can be
obtained from the vehicle's manufacturer. |
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Oxides of Nitrogen |
Commonly known as NOX, it is various combinations of one part
nitrogen and one or more parts of oxygen, which is a by-product of
combustion at a very high temperature when using gasoline as a fuel.
NOX is a component of smog. |
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Oxygen sensor |
The oxygen sensor is part of the exhaust and emission systems and is
usually located in the exhaust manifold. It senses the amount of
oxygen in the exhaust gases and adjusts the fuel system's operation
accordingly to minimize emissions while improving economy and
performance. |
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P |
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Park (gear) |
This is a gear found only on automatic transmissions. The park gear
locks a vehicle's transmission in place, preventing the car from
moving. |
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Park/neutral safety switch |
This is a switch found on many modern automatic transmissions that
prevents a vehicle from starting unless the gear selector is in park
or neutral. |
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Parking brake |
Also known as the emergency brake. The parking brake is used when
parking on an incline to prevent the car from rolling away. The
parking brake is usually cable operated and can be used as a backup
if the regular hydraulic brake system fails. |
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Parking brake cable |
The parking brake cable connects the parking brake pedal or handle
to the parking brakes themselves. |
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Parking brake shoes/pads |
The parking brake shoes/pads are just like normal brake pads or
brake shoes. The only difference is that they work specifically with
the parking brakes, and are independent from the regular brake
system. |
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Petcock |
A
small valve used for draining liquids. Petcocks are usually
associated with radiators and are located at the bottom of one of
the radiator's tanks. |
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|
Pinging (engine) |
A
noise made in the engine caused by a pre-ignition condition. When
your engine knocks or pings, it is a sign that the engine is firing
at the wrong time. This could be because of improper ignition
timing, an incorrect grade of gas, or another ignition or fuel
system fault. |
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Piston |
An
aluminum-based cylindrical part located inside an engines cylinder
(combustion chamber) that moves up and down, transferring the force
of combustion to the connecting rod and then to the crankshaft,
which causes rotation. |
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Piston Ring |
Usually 3-4 rings that fit on the outer diameter of the piston
beneath the piston top which seals the pressure of combustion in the
cylinder (top 2 or 3 rings called the compression rings) and aids in
scraping residual lubricating oil from the cylinders walls (bottom
ring called the oil ring). |
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Piston-To-Valve Clearance |
The distance or space between the intake and exhaust valves in
relation to the top of the piston when the piston is at the top of
its stroke, known as TDC, or top dead center. |
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Pitman Arm |
Arm attached to the pitman shaft on a steering box that moves the
relay rod as the steering wheel is turned in a mechanical (not rack
and pinion) steering system.. |
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Plastic polish |
A
special type of polish designed to gently remove scratches and
yellowing from plastic items such as convertible top windows and
plastic lenses. |
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Play |
Play occurs when there is excessive free movement in a vehicle's
steering system. For instance, if you turn your steering wheel
either direction from the center and nothing happens for the first
two inches of travel, your steering system has play in it. |
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Porting |
The enlarging of the exhaust and intake passages to increase flow
through the cylinder head. When done correctly, this process can add
a significant amount of power and increase fuel efficiency. |
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Posi |
Also known as Positraction, which is a limited-slip differential
(LSD) distributing power equally to both drive axles through a
series of plates, clutches and springs. |
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|
|
Positive Crankcase Ventilation (PCV) |
This system relieves pressure and recirculates fumes created by the
motion of the crankshaft, connecting rods and pistons in the
crankcase, by sending them through a one-way valve back into the
engine to be burned in the combustion process. |
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|
|
Power Steering |
A
system which provides additional hydraulic force, generated by a
pump, to the steering mechanism, either a steering box or rack,
reducing the driver's turning effort at the steering wheel. |
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|
|
Power steering fluid |
A
special type of fluid designed for power steering systems. |
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|
|
Power steering pump |
The power steering pump transfers power steering fluid under
pressure to other power steering system components, allowing the
driver to steer with minimal effort. |
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|
|
Power train |
The elements of a vehicle by which motive power is generated and
transmitted to the driven axles. Examples of power train components
are the engine, transmission and differential. |
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|
|
Power train Control Module (PCM) |
A
module commonly referred to as the vehicle's "main computer", it
controls how the engine and transmission operate via input from many
sensors. Aka: ECM (Electronic Control Module), EEC (Electronic
Engine Control) and ECU (Electronic Control Unit). |
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|
|
Prechamber |
A
dual-chamber combustion system for diesel engines with a centrally
located auxiliary combustion chamber for reduced emissions and less
diesel soot. |
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|
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Pressure (Absolute) |
The pressure referenced to a perfect vacuum, usually found in the
intake manifold. Commonly known as the MAP, or Manifold Absolute
Pressure. |
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|
|
Pressure (Atmospheric) |
The pressure of the air outside of the engine at any given
temperature and altitude. Sometimes called barometric pressure, it
is usually referenced as the "baro" sensor reading in the power
train control system. |
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|
|
Pressure (Differential) |
The pressure difference between two areas in the engine, such as
between the pressure in the intake manifold and the atmospheric, or
outside, air pressure. |
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|
|
Pressure Plate |
The part of a manual clutch system with a covered spring and
clamping ring mounted over the friction disk, to the flywheel. When
the pressure plate is engaged, it clamps the friction disk to the
flywheel, which turns the input shaft of the transmission. It allows
the smooth application of power to the transmission. Also known as a
clutch cover. |
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|
|
Primer |
A
type of paint applied to a vehicle's surface to increase its
compatibility with the topcoat and/or to improve the corrosion
resistance of the base metal. The primer paint is applied first,
then the final topcoat, or color coat of the vehicle is applied on
top of the primer coat. |
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Proportioning Valve |
A
valve in the brake hydraulic system usually located in or near the
brake master cylinder that controls pressure to the rear wheels to
achieve better braking balance front-to-rear. |
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Pump |
A
device used to transfer fluids or air by suction, pressure, or both.
An example of this is an oil pump for the vehicle's engine, or the
pump that raises and lowers the air pressure in a vehicle's air-ride
suspension system. |
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Pushrod |
Pushrods are used in engines with overhead valve (OHV) designs. The
camshaft in the engine block pushes up on the lifters and then on
the pushrods, which then push the rocker arms, which then open the
valves. |
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R |
back to top |
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Radial |
Referring to a type of air conditioning compressor that compresses
its refrigerant using a radial, or round, piston and cylinder
arrangement. It's a fairly light unit and is associated with 1982
and newer GM vehicles and used R12 and R-134 refrigerant. Compare to
Axial. (Remember, Axial is LONG like an axle; Radial is SHORT like a
radial tire.) |
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Radiator |
A
radiator is a liquid-to-air heat transfer device having a tank(s)
and core(s) specifically designed to reduce the temperature of the
coolant in an liquid-cooled internal combustion engine. Radiators
can be made from aluminum or copper-brass. |
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Radiator cap |
The radiator cap maintains a specific pressure in the cooling system
so it operates efficiently. |
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Rail |
A
manifold for fuel injection which distributes fuel to the fuel
injectors, often called a fuel rail. They are usually made from an
aluminum extrusion or steel pipe. |
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Ram Air |
Type of induction where fresh air is fed through the hood or
underneath the vehicle and sent to the intake via the air filter.
With the reduced air temperatures associated with fresh,
non-underhood, ram air, more power and efficiency is generated. |
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Rear-wheel drive (RWD) |
Rear wheel drive cars transmit power to the ground through the rear
wheels. |
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Refrigerant |
Commonly referred to as freon, it is a substance used as a heat
transfer agent in an air conditioning system. There are two types
being used in vehicles today; R134 for newer cars and R12 for older
vehicles. Because R12 refrigerant is harmful to the environment when
it leaks into the atmosphere, it is being phased out in favor of
R134. |
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Regulator (Voltage) |
A
device that automatically controls the output of another device by
adjusting the voltage to meet a specified value. Example: an
alternator can put out over 14 volts, but by sending the voltage
through a regulator, it only allows 12 volts output. |
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Relay |
A
electromechanical device in which connections of a higher voltage
circuit are operated by a lower voltage circuit to divert the
current. High-output auxiliary driving lights contain relays in
their circuits so as not to overload and burnout the on-off switch. |
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Remanufactured |
A
component or piece of equipment that has been rebuilt and restored
to its OE (original equipment) specifications to function as new.
Common examples of rebuilt parts include alternators, water pumps,
carburetors and power steering pumps. |
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Reservoir |
Reservoir is a generic term that refers to any container for a
fluid. For instance, most vehicles have a windshield washer fluid
reservoir and a brake fluid reservoir. |
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Revving the engine |
Increasing the RPM's of an engine without allowing the power to be
transferred to the wheels. When your car is in park or neutral and
you press on the gas without the intention of making the car move,
you are revving the engine. |
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Rheostat |
Rheostat refers to a control which varies the intensity of the
lights and speed of certain accessories that it is connected to. For
instance, an instrument lighting rheostat controls the brightness of
the instrument lighting. |
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Riding the clutch |
When driving along, if you rest your foot on the clutch pedal, you
are riding the clutch. This practice causes excess wear on the
clutch and the clutch throw-out bearing. |
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Rocker arms |
Rocker arms are used in overhead valve (OHV) engines. They are
operated by pushrods and open and close the valves. |
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Roller Cam |
A
camshaft which uses lifters, either hydraulic or mechanical, using
rollers at the base of each lifter which contacts the cam. These
high-strength steel cams reduce friction and emissions and increase
power and efficiency with optimized lobe designs. |
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Rotary engine |
A
rotary engine does not have pistons or cylinders; instead, it has
triangular shaped rotors that move in an elliptical path within
chambers to create power. The only companies that have offered
rotary cars for sale are Mazda, NSU, and Citroen. |
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Rotor- Brake |
A
disc made from cast iron or steel, rotating on an integral or
separate hub near the wheel of a vehicle and is stopped by friction
pads located on either side of a hydraulically-operated brake
caliper. |
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Rotor-Distributor |
An
electrically conductive component mounted to the rotating
distributor shaft that transfers electrical energy from the
centrally located coil terminal to the individual cylinder terminals
within the distributor cap circumference. Also known as an ignition
rotor. |
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Rubbing compound |
A
rubbing compound is a type of paint polish that contains extremely
fine abrasive particles. These particles remove the top layer of
paint, eliminating shallow scratches, and revealing the shiny paint
layer underneath. |
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Running Board |
Usually a long, flat board that runs along the rocker panel of a
truck or SUV, which is used to help passengers step in and out of
the vehicle. |
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Running rich |
This is a condition that occurs when too much gas and too little air
is being fed to the engine. A sign of rich running is black, sooty
exhaust. |
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Rust-converting primer |
Rust-converting primer is a special type of primer paint that stops
the progress of surface rust. |
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S |
back to top |
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Scan Tool |
A
device that interfaces with, and communicates vehicle information to
and from a vehicle's power train control module or computer, via an
onboard data link. |
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Sensor |
The name for a device that senses the absolute value or a change in
a physical quantity such as temperature, pressure, rotation or flow
rate, and converts that change into an electrical signal, which is
then sent to the vehicle's power train control module (PCM). |
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Serpentine belt |
A
serpentine belt is a wide single drive belt that drives certain
engine accessories (alternator, power steering pump, air
conditioning compressor, etc.). It's a type of fan belt with
multiple grooves that fit into similar grooves on the pulleys. Also
know as a multi-groove belt, micro-groove belt, or multi-v belt. |
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Shift linkage |
This is a series of rods and/or cables that connect the gearshift
lever or gear selector to the transmission. |
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Shift Solenoid |
A
PCM-controlled electromechanical device which regulates shift
firmness and rpm in an electronically-controlled automatic
transmission. |
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Shock Absorber |
A
component using friction to dampen and control a vehicle's
suspension up and down movement. Modern shocks are of the hydraulic
type, using an oil to dissipate the heat of friction to the outside
air. They contribute to your vehicle's ride quality. See also Strut. |
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Short (circuit) |
A
short circuit occurs when there is a break in an electrical circuit
and the circuit finds a new ground source. |
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Shroud |
A
metal or plastic cover used to isolate rotating components or hot
parts of the vehicles' engine or exhaust system. A radiator shroud
surrounds the radiator fan and helps direct incoming air through the
radiator and to the front of the engine as well as protecting the
radiator and fan from foreign objects. |
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Single overhead cam (SOHC) |
A
type of overhead cam engine with a single cam that operates both the
intake and exhaust valves. |
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Solenoid |
A
device consisting of an electrical coil, and when energized,
produces a magnetic field in a plunger and is pulled to a central
position. A solenoid may be used as an actuator in a valve or
switch. Power door locks use a solenoid-activated actuator. |
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Spark Plug |
Part of the ignition system, it's an electrical device with a ground
and center electrode where a spark is created between the two by a
high voltage current from the distributor. The spark ignites the
fuel/air mixture in the combustion chamber at the top of the
compression stroke. |
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Spark plug electrode |
The electrode is the curved piece(s) of metal (ground electrode)
that reaches over the center electrode. The spark is created between
the electrodes. |
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Spark plug gap |
Gap is the precise distance between a spark plug's center and ground
electrodes. |
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Spark plug terminal |
The terminal is the metal part of a spark plug above the ceramic
insulator that the spark plug wire attaches to. |
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Spark plug wires |
Spark plug wires are the cables that conduct the electric pulses
from the distributor cap to the spark plugs. Also called ignition
wires. |
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Speedometer |
An
instrument that indicates a vehicle's speed in miles or kilometers
per hour. |
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Sprag |
A
transmission internal component load carrying element, usually
consisting of roller bearings and a cage element. Heavy duty sprags
have more bearings, therefore a greater load capacity. |
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Springs (suspension) |
Springs absorb road imperfections and vibration, help hold the
suspension up, and help vehicles handle better. Also called coil
springs, or leaf springs. |
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Stabilizer bar |
See Sway bar. |
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Starter motor (starter) |
This is the electric motor that turns your engine over when you turn
the key in the ignition switch. |
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Starter solenoid |
This is a large relay that controls the operation of the starter
motor. |
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Starting system |
The starting system consists of the starter motor, starter solenoid,
battery, ignition switch and ignition key. |
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Steering lock |
The steering lock is a theft prevention device that locks the
steering wheel in place when the key is removed from the ignition
switch. |
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Steering system |
The steering system allows you to control the direction of your
vehicle. Most modern cars have a rack and pinion steering system
with a power assist. Components in your steering system include the
steering rack, tie rods, tie rod ends, ball joints, power steering
pump, power steering hoses, and the pump drive belt. |
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Stroke |
The distance traveled by the piston in its cylinder from top dead
center to bottom dead center. The stroke is determined by the throw
of the crankshaft, and is a determining factor in the displacement
of an engine. |
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Struts |
Struts are part of your vehicle's suspension, and do the same job as
a shock absorber. A vehicle will either have struts or shock
absorbers, or a combination of both (i.e. struts in the front, and
shock absorbers in the rear). They regulate how much your vehicle
can move up and down, and keeps the tires in contact with the road
surface after going over a bump. |
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Supercharger |
A
mechanically driven device, usually off the crankshaft, that
pressurizes the intake air, and in turn increases the density of the
air/fuel mixture and subsequently increases the power output of a
given engine displacement. |
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Suspension |
The suspension connects the vehicle body to the frame. A well tuned
suspension helps the vehicle to handle better, while increasing
comfort and isolating passengers from bumps and vibration. |
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Sway bar |
The sway bar is a suspension system component that helps to minimize
the lean of a vehicle when cornering. Also called a stabilizer bar. |
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Synchromesh |
Synchromesh is a feature that allows you to upshift and downshift a
manual transmission without grinding gears. It does this by
synchronizing, or evening out, the speed of the engine and the speed
of the gear you are selecting. If the transmission didn't have
synchromesh, you would either have to match the engine speed to the
gear speed (known as double-clutching) or else grind the gears every
time you shift. This term is often shortened to just "synchro". |
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T |
back to top |
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Tachometer |
An
instrument that indicates engine speed in revolutions-per-minute
(rpm). It measures the speed that the crankshaft is rotating. |
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Tailpipe |
The part of an exhaust system where exhaust gasses exit the car body
from the rear of the vehicle. The tailpipe connects the muffler to
the tailpipe tip (sometimes called a spout). The tailpipe tip is the
part of the exhaust system that you can see sticking out from under
the rear bumper. |
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Thermostat |
The thermostat is a valve located in the cooling system of a vehicle
that automatically regulates the coolant flow through the radiator
and engine based on the coolant temperature. |
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Throttle |
A
mechanism for regulating the supply of the fuel/air mixture to an
internal combustion engine, thereby regulating the speed of the
engine. Aka; accelerator pedal |
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Tie rod |
Part of the steering system, the tie rod connects the
spindles/wheels to the rest of the steering system. |
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Timing (ignition timing) |
Timing refers to the moment when the spark ignites the air/fuel
mixture in the engine's combustion chamber. Timing needs to be set
exactly right for an engine to run correctly. |
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Timing belt |
Timing belts are rubber belts that connect an engine's camshaft to
its crankshaft. If a timing belt breaks, these two components will
get out of synch, which can cause potentially significant engine
damage. |
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Timing chain |
Timing chains are metal chains that connect an engine's camshaft
gear to its crankshaft gear. Timing chains ride on sprockets that
eventually wear out and can cause sloppy timing. When this happens,
it is time to replace the sprockets and chain. If a timing chain
breaks, the camshaft and crankshaft will get out of synch, causing
potentially significant engine damage. |
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Timing gears |
Timing gears are part of a timing chain system that connects the
engine's camshaft to its crankshaft. On some vehicles, the camshaft
gear meshes directly with the crankshaft gear, eliminating the
timing chain. |
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Timing light |
A
timing light is used to check or set ignition timing. |
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Tire gauge |
Tire gauges are used to measure the air pressure of a tire. You
should always check tire pressure when your tire is cold (when the
vehicle hasn't been driven for about an hour). |
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Tire valve |
The fitting in the valve stem of the wheel that allows you to
inflate or deflate the tire. |
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Tonneau |
An
accessory cover fitted to protect a vehicle bed or driver's
compartment, most often on pickups and early autos. A tonneau can be
constructed of fabric, metal or fiberglass. In addition to sealing
the vehicle bed or passenger area, it also contributes to vehicle
appearance. |
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Torque converter |
A
fluid coupling device which multiplies torque between an engine and
automatic transmission/transaxle. It allows smooth power transfer
from the engine to the transmission. When a vehicle is stopped, a
converter allows enough fluid slippage so that the engine can idle
without stalling. |
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Transaxle |
Transaxles are a combination of components; the transmission and
differential. Most front-wheel drive cars have transaxles. However,
some rear wheel drive cars, such as some Porsches, new Corvettes and
Alfa Romeos, have rear-mounted transaxles. |
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Transducer |
A
device that receives an electrical signal from one system and
transfers it, often in a different form, to another system. Example:
the cruise control transducer converts a vehicle speed signal to a
vacuum to control the servo attached to the throttle. |
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Transfer case |
Used in 4X4 vehicles to transfer power to the front and rear
differential assemblies. There are different selectable ranges to
maximize traction in varying road or trail conditions. |
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Transmission |
A
component of the power train of a vehicle which selects gear changes
(either manually or automatically), which can increase or decrease
the speed and power between the engine and the drive axles. |
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Transmission fluid |
Transmission fluid (ATF) is specially developed to allow automatic
transmissions operate smoothly and efficiently. Automatic
transmission fluid needs to be checked and replenished periodically. |
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Transmission interlock |
A
safety device found on many modern automatic transmissions that
prevents the drive or reverse gear from being selected until the
brake pedal is pressed. |
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Transmission linkage |
This is a series of rods and/or cables that connect the gearshift
lever or gear selector to the transmission, allowing the shifting of
gears. |
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Transmission mounts |
Transmission mounts are often made of steel and rubber. Transmission
mounts help support the transmission, and also help to prevent
transmission vibrations from being transmitted to the car interior. |
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Transmission oil |
Transmission oil is specially developed to allow manual
transmissions to operate smoothly and efficiently. Transmission oil
rarely needs to be replenished. |
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Travel |
Travel is a measurement of how much movement, or play, occurs in a
given system. |
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Trinary |
Consisting of three (3) parts, or a progression of a multiple of
threes (3). |
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Tune up |
A
procedure during which a series of parts that wear out (spark plugs,
ignition rotor, distributor cap, etc.) are replaced to bring the
engine back into proper operating specifications. In addition,
timing is normally checked and reset. A tune up is usually performed
according to a schedule. |
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Turbocharger |
A
centrifugal device driven by exhaust gases that pressurizes the
intake air, increasing the density of the air and consequently
increasing the power output from a given engine displacement. A
turbocharger will boost the power of an engine. Aka turbo. |
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U |
back to top |
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Universal joint |
Universal joints are part of a car's driveline. They allow the
driveshaft to continue to rotate at all angles. |
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V |
back to top |
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Vacuum |
A
condition in which pressure has been reduced below the ambient
atmospheric pressure. Vacuum is created in the intake manifold and
can be used to operate a power brake booster. |
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Vacuum hose |
Vacuum hoses connect between vacuum-powered accessories and a vacuum
source such as the engine's intake manifold. |
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Valve |
A
device by which the flow of a liquid, gas or vacuum may be
controlled. Example: the intake and exhaust valve in the cylinder
heads start and stop the flow of the incoming fuel mixture and
outgoing combusted exhaust gases. |
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Valve cover |
The valve cover is the metal cover that is attached to the top of
the cylinder head. It allows technicians access to the engine valves
and rocker arms for adjustment and checks. |
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Valvetrain |
Components actuated by the camshaft and can include valve lifters,
pushrods, rocker arms and valve springs. |
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Vapor lock |
Vapor lock occurs when an engine gets so hot, it boils the fuel
traveling through the fuel lines. This creates vapor, preventing the
fuel from traveling through the lines, causing the engine to stop
running. |
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Variable-assist power steering |
A
power steering system designed to vary the level of power assist
according to vehicle speed or angle of the steering wheel. |
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VIN Code |
The VIN
(Vehicle Identification Number) can be found by looking at the
dashboard on the driver side of the vehicle. If the VIN cannot be
found, open the driver side door and look at the door post (where
the door latches when it is closed). It is likely that the VIN will
also be displayed in this location. |
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Voltage regulator |
The voltage regulator limits the power output of the alternator to
prevent overcharging the battery and electrical system. |
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W |
back to top |
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Washer fluid |
This is special fluid designed to help clean the windshield quickly
and with little residue, used in conjunction with the wiper blades. |
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Washer fluid reservoir |
The container where washer fluid is kept in a car, usually located
under the hood. |
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Washer nozzles |
These are the jets on the hood or in the wipers that spray washer
fluid onto the windshield. |
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Washer pump |
An
electric motor that delivers washer fluid to the washer nozzles for
cleaning the windshield with the windshield wipers. |
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Wastegate |
A
valve on a turbocharged engine that limits air pressure in the
intake tract by allowing the pressure to bypass to outside air,
after the turbocharger. |
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Water in fuel warning light |
This is a warning light found only on diesel-engine cars. Because
diesel fuel collects water, a sensor in the fuel tank will indicate
when the ratio of diesel fuel to water reaches a certain level. |
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Water pump |
Part of the cooling system, the water pump circulates coolant,
helping the engine to stay in the desired temperature range. |
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Wax |
Wax is a product used to protect paint finishes and create extra
shine. |
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Weather-stripping |
A
rubber gasket found around vehicle openings to seal out water and
wind. Weather-stripping is located around doors, windows and trunks. |
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Wheel bearing |
A
bearing or bearing assembly located at each wheel allowing the wheel
to spin around the axle with minimal wear and friction. Front wheel
bearings are contained within the hub, and are sometimes integral to
the hub. A wheel bearing set consists of an inner and outer bearing. |
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Wheel cylinder (brakes) |
The wheel cylinder is used with drum-type brakes. When the brake
pedal is pushed, the wheel cylinder pushes the brake shoes against
the drum brake, slowing or stopping the car. |
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Wheel nuts |
Wheel nuts are used to attach a wheel to a hub. |
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Wiper arms |
The part of the windshield wipers that are between the wiper pivots
at the base of the windshield and wiper blades. |
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Wiper blades |
The rubber part and carrier assembly of the windshield wiper that
clears the windshield. |
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Wiper refill |
The rubber part of the wiper blade that makes contact with the
windshield. A wiper refill will insert into a wiper blade. |
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Wire (electrical) |
An
insulated conductor used in an electrical system to transmit
electricity from one component to another. If a wire breaks, it
creates an open circuit. If a broken wire make contact with a
grounded surface, it creates a short circuit. |
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