A component in a car's air conditioning system that
serves two purposes: 1- removes moisture from the
refrigerant chemical; 2- provides a storehouse where
refrigerant chemical can accumulate until it is needed to
do its job.
A chemical solution that is added to gasoline, motor oil
or transmission fluid with the objective of enhancing
A safety restraint device that deploys when it senses
there has been severe deceleration of the vehicle.
A pump whose purpose is to create pressurized air. This
air can be used to power such things as the air-ride
suspension systems or air brakes.
A pump whose purpose is the pump the refrigerant chemical
through the air conditioning system.
Air conditioning refrigerant chemical is pumped through
the condenser at extremely hot temperatures and under
high pressure, 80 to 300 PSI, depending on the
environmental conditions. The condenser acts as a
radiator, cooling off the refrigerant.
A spoiler located beneath the front bumper shaped to
reduce the airflow under the car, lower aerodynamic drag
and reduce lift.
A filtering device designed to clean the air taken into
the engine's fuel delivery system.
A mixture of air and fuel that the fuel management system
The process of positioning wheels into a correct
relationship with each other and with the
A tire that gives maximum traction under all weather
The All-Wheel Drive System is used on a lot of cars where
a high-low range is not needed. Think of the all-wheel
drive system as a permanent 4WD system, but without the
two-speed transfer gearbox. There is no high and low
range, and the system is always in automatic four-wheel
This unit converts the 12-volt DC (Direct Current) from
the battery into AC (Alternating Current) at the rate of
13.8 to 14.2 volts, which is necessary to operate your
car's performance and electrical systems.
A chemical solution (Ethyline glycol) that lowers the
freezing point and raises the boiling point of the engine
BRAKING SYSTEM (ABS)
When ABS-equipped brakes are pressed hard (for instance
in the case of a panic stop) the ABS system pumps the
brakes up to 30 times per second to prevent them from
locking up. ABS helps the driver maintain control and
stop the car in a straight line, rather than spinning out
A suspension component that reduces body roll.
A transmission where the gears are shifted automatically
by a computer though the use of hydraulics and
A steel shaft that connects the differential to the drive
Oscillatory rotation of a solid axle about its axis due
to driving or braking torque, usually when located by a
Some drive systems require manual "locking in"
of the front wheels in order to drive in 4 wheel drive,
because they freewheel when the 4 WD is not engaged. On
vehicles equipped with automatic hubs, "locking
in" the front wheels requires only the flip of a
A flexible ball and socket joint used primarily in front
A rigid axle supporting the non-driven wheels.
The line that separates a car's greenhouse from its lower
The vehicle takes longer to stop the second or third time
brakes are applied due to a buildup of heat in friction
A hydroscopic fluid (absorbs water) with a high boiling
point, used in hydraulic brake systems.
A device consisting of two plates lined with brake pads
that press against the sides the disc rotor to slow it's
Inclination of a wheel outward with respect to the body.
Inclination of the steering axis in the longitudinal
An emissions control device that is part of the exhaust
system. Its purpose is to reduce harmful tailpipe
emissions caused by the engine. The catalytic converter
lowers exhaust emissions by creating a catalysis
(chemical reaction) within itself. Here is how it works:
Hot exhaust gas flows through the converter, which is
filled with sulfur or platinum balls. The sulfur or
platinum heats up to combustion temperatures, thus
burning any unburned gases that might be in the exhaust
flow, reducing tailpipe emissions.
The frame of the car which provides the strength and
serves as the foundation of the vehicle. The body,
engine, drivetrain components, and suspension are
attached to the chassis.
Protective and decorative panels along the lower body.
A coupling device used to engage or disengage the flow of
power from the engine to the transmission.
A safety device that prevents a car from being started
while it's in gear. The clutch must be depressed for the
engine to start.
VARIABLE TRANSMISSION (CVT)
An automatic transmission that uses belts and pulleys
instead of gears wheels to allow an infinite number of
Front and rear portions of a vehicle's body that are
designed to crush progressively to better absorb the
energy of a crash.
RUNNING LIGHTS (DRLs)
Lights that automatically turn on when the vehicle is
Rapid, uncontrolled fuel combustion in the combustion
chamber, which can cause severe engine damage.
The components that are responsible for transferring
power to the drive wheels of your vehicle. Some of the
major components in the drive train include:
transmission, differentials, transfer case, drive shafts
and half shafts wheel bearings, and universal joints.
A valve designed to meter the flow of refrigerant in the
vehicle's air conditioner, based on the heat load it
senses coming from the evaporator core.
The cold air that comes from your car's air conditioner
comes from this core. A chemical is pumped through the
evaporator core (which is much like a small radiator or
heater core). The evaporator carries the cold chemical
into the car where an interesting exchange takes place
... the chemical exchanges cold air for hot air! It
literally saps the hot air out of the car by absorption.
The cold air that is radiated from the evaporator is then
blown into the car's ventilation system, cooling you
down. Dehumidification also takes place during air
conditioning. Ever wonder where all that water comes from
that drips under your car? Now you know!
The front of a vehicle - grille, headlights, bumper and
A method of payment for the work of automotive
technicians. If an operation calls for a time frame of
two hours (called the "flat rate" for that
job), than the labor charge will be 2X the shop's hourly
rate. If the technician is proficient at this particular
operation and is able to do it in half the time, the
customer still pays for two hours of labor, and the tech
earns two hours of pay for one hour of work. Conversely,
if the tech does the job in more than the allowed time,
the customer still pays for two hours. This method of
payment holds a standard hourly rate for the customer,
and yet rewards high skilled technicians.
The largest stamped metal part in a car's body, it forms
the floor and also provides the attachment points for
many of the car's mechanical parts.
A metal disc bolted to the end of the crankshaft. The
inertia of the spinning flywheel while the engine is
running smooths the engine's operation.
Three sub-terms are defined under this heading: Full
time 4WD, Part Time 4WD, and Permanent
4WD. FULL TIME 4WD: The most
commonly used 4 WD system on the market. Full time 4WD
offers both a two-wheel drive mode for summertime driving
or dry-road conditions, and an automatic 4WD mode for
changing road conditions. There is also 4WD high and 4WD
low modes for when the going really gets tough. The
automatic 4WD mode makes this system convenient for many
drivers. In addition to the transmission and transfer
gearbox, a center differential is used to couple the
front and rear wheels. The differential allows the front
and rear wheels to turn at different speeds as needed,
letting the full time 4WD work automatically. Very
simply, when engaged in automatic 4WD on a dry straight
road, the system operates in two-wheel drive. When the
wheels start to spin due to slippery road conditions, the
system reacts by progressively locking the front and rear
wheels together to optimize traction. This system is
limited in that it requires the driver to determine when
to engage it. PART TIME 4WD:
This is the most basic of all 4WD systems. It gives the
driver the ability to choose when to drive in two-wheel
drive or 4WD. This is all good and well, until you
realize that you really can't engage the 4 WD on pavement
unless it is very, very slippery. That is because, when
you engage 4WD with this system, you lock the front and
rear wheels together through the transmission and
transfer gearbox. This is great for straight-ahead
traction on very slippery surfaces. However, on dry
pavement it makes for odd driving, cornering, and
handling characteristics. Also, you can harm the drive
train components by driving in 4WD for extended periods
while on dry pavement. So why choose this type of system?
Three reasons: 1. It is less costly to build and
therefore to purchase 2. It is often very durable under
heavy stress 3. When you don't need 4WD, you can
disengage it. PERMANENT 4WD: This system
is similar to full-time 4WD, but it has no two-wheel
drive mode. The vehicle is always in 4WD, so you don't
have to determine whether conditions are right to engage
it. It still has transmission, transfer gearbox, and
center differential coupling the front and rear wheels.
The only difference is that torque (power) is constantly
being applied to all the wheels, giving maximum traction
in all weather and road conditions. Current systems have
high and low modes for when the going gets tough. However
(and most importantly), the system does the thinking for
you. It automatically applies as much lock up (to all the
wheels) as necessary for maximum traction.
Fuel injection is an electronic fuel delivery system that
increases performance and fuel economy. It achieves this
by monitoring engine conditions and providing the correct
air/fuel mixture based on the engine's demand. Unlike a
carburetor, which mixes fuel and air together before
loading it into the intake manifold (and ultimately, the
cylinder intake port), fuel injection injects the fuel
directly into the combustion chamber through the cylinder
head. This enables more precise control over the quantity
and air/fuel mix, thus delivering optimum performance and
economy. The need for a carburetor is eliminated, as well
as the need for complex and imprecise tuning.
The standard unit of measurement of an engine's power.
One horsepower is the amount of energy needed to lift 550
pounds one foot in one second.
A sensor that detects the point of detonation in the
engine's cylinders. The knock sensor sends this
information to the car's computerized engine-control
system, which makes adjustments to keep the engine
operating near its detonation limit and running more
A differential that detects slippage in one wheel and
sends torque to the other wheel which is not spinning. It
Locks both wheels on the axle, forcing them to turn
together and allowing for maximum traction.
The hydraulic pump that pushes the brake fluid through
the brake lines, ultimately applying the brakes.
A component that combines a coil spring and a shock
The measure of the anti-knock properties of gasoline. The
higher the octane number, the less likelihood of
A gear ratio that reduces engines RPMs at highway speeds,
thus improving fuel economy.
The roof supports on either sides of a car's windshield.
A system that uses a hydraulic pressure booster to reduce
This steering system allows for more responsive handling
and is found mostly in newer cars. It consists of a
steering shaft that is controlled (or turned) by the
steering wheel. At the end of the shaft there is a small
gear called the pinion gear. The pinion gear meshes with
a toothed bar called the rack. This bar is connected to
the steering linkage (tie rods) that control the two
front wheels. When the steering wheel is turned right or
left, the rack is moved right or left, resulting in the
steering of the vehicle.
A type of tire in which the cords of the body plies run
at right angles (radially) to the tire's centre line.
A steering mechanism which uses a worm gear that meshes
another gear that actuates the steering arm. Ball
bearings in a recirculating track reduce friction between
the two components.
The lower portion of a car's body between the front and
rear wheel openings.
A variation of the internal combustion engine perfected
by Felix Wankel during the 1950s and 60s which uses a
triangle-shaped rotor instead of conventional cylinders
Shock absorbers cushion road vibration and bumps. They
are connected to the wheel and the car frame and are
filled with oil, and sometimes air or nitrogen, to soften
the shock of rough roads.
Angles at which the steering's components and related
suspension parts are set. These affect handling and
include camber, caster, toe-in, and trail.
A mechanically driven air compressor that increases the
amount of air-fuel mixture supplied to the engine to
increase power output.
A vehicle's suspension system is made up of the
components on which the vehicle rides. These include
shock absorbers, struts, springs (coil or leaf), sway
bars, ball joints, control arms, or torsion bars. These
parts work together to provide a smooth comfortable ride,
as well as good control and handling of the vehicle. They
take a beating on a daily basis and therefore wear out.
This wear causes the alignment angles to go out of
adjustment, which results in tire wear and poor handling.
That is why it's a good practice to have alignment checks
every 12,000 miles or 12 months, whichever comes first.
An instrument used to used to measure engine speed in
revolutions per minute (RPM).
Many of today's cars are equipped with a timing belt in
place of the old timing chain. The function of this small
yet critical member is to keep your engine mechanically
"in time." How they work: In a four-stroke
internal combustion engine (intake, compression, power,
exhaust) the top half of the engine must be synchronized
(or in time) with the bottom half to complete the four
stroke cycle. The timing belt achieves this by meshing
with cogs connected to the crankshaft and camshaft. The
driving of these components in perfect time achieves the
four stroke cycle, producing power in the engine. The
timing belt is made out of rubber and is subject to wear
and tear due to mechanical and environmental conditions.
The bottom line with timing belts is to have them checked
every 25,000 miles and replaced every 50,000 miles.
Telltale signs of a failing belt are cracks, cuts, worn
or broken teeth, and deterioration from wear and exposure
to harmful fluids and/or high temperatures. If the belt's
teeth are gone, the valve timing can be affected by
either excessive advancement or retardation, resulting in
poor engine performance. If the belt breaks, major engine
damage can occur on some engines.
Traction control is an option on many cars today. When
engaged, it "senses" when a driving tire has no
traction. The system will then conpensate for this by
slowing the spinning wheel through partial application of
the brake. The system uses wheel speed sensors to monitor
the wheel speed. When traction is lost, the sensor
prompts the brake computer to partially apply the brake
to the wheel that is spinning, allowing it to gain
traction. I call it "Antilock brakes in
reverse." This system improves traction in areas
where it may normally be hard to do so (snow, gravel, and
rain). Traction Control has its origins in Formula 1
Racing where optimum traction is a must for safety and
A combination of transmission and differential found in
front-wheel-drive vehicles. The differential is inside
the transaxle, and the drive axles are connected through
constant velocity joints (CV joints) to the wheels.
An auxiliary gearbox attached to the transmission, which
allows you to shift into a high and low range for serious
Similar to a supercharger but powered by exhaust gases.
A joint that transmits rotary motion between two shafts
that are not in a straight line.
A valve is a device that is controlled mechanically or
electrically to meter or prevent the flow of a liquid or
gas. Most internal combustion engines use intake and
exhaust valves to control the flow of the air/fuel
mixture into the combustion chamber and to exhaust burned
gases. Some engines have up to four valves per cylinder
to increase efficiency and performance. Valves are used
in other automotive applications as well. Cooling
systems, transmissions, and air conditioning systems use
valves where metering of a liquid or gas is necessary.
The valve body is the brain of the transmission. Up and
down shifting is controlled by the valve body through
hydraulic pressure and electronic commands from the
vehicle's performance system. The valve body directs the
flow of transmission oil to where it is needed in order
for the transmission to perform a function (for example,
the application of "passing gear"). The
environment within which the valve body operates must be
sterile. Varnish buildup and wear material can clog the
valve body, causing erratic shift patterns of the
transmission. This is why the transmission fluid and
filter should be changed every 30,000 miles.
The components which cause the valves to open and close,
including the camshaft, tappets (or, cam followers),
pushrods, rocker arms, valve springs and valves.
IDENTIFICATION NUMBER (VIN)
A 17-digit combination of letters and numbers unique to
each vehicle. It is located on the driver's side of the
dashboard at the base where the windshield glass and
The resistance to flow of a liquid, such as motor oil.