A list of car parts/automotive terms beginning with the letters A through F . . .

ABS/Antilock Braking System Also known as anti skid brakes, modern ABS systems electronically monitor the speed of the wheels and regulate the hydraulic pressure accordingly. The aim is to maximize braking power while preventing the wheels from locking and skidding.

A chemical added in small quantities to a petroleum product to improve certain chemical or physical properties.
Air Conditioning (A/C) A system that cools and dehumidifies air entering the passenger compartment. The system uses a refrigerant to cool the air and carry heat away from the passenger compartment. Major system components include a compressor, 
condenser, evaporator, accumulator or receiver/dryer, and orifice tube or expansion valve.
Air Filter
A filter that prevents dirt and debris from air entering the engine.
Airflow Sensor
A device that's used in many electronic fuel injection systems for measuring the volume of air entering the engine. Some use a spring-loaded vane while others use a hot wire or heated filament to sense air flow.
All Wheel Drive (AWD)
A vehicle (usually a car) where all four wheels are driven. Most are fulltime systems for year-round driving, and use a viscous fluid coupling center differential instead of a transfer case to route drive torque to all four wheels. This 
allows the front and rear wheels to turn at slightly different speeds when turning on dry surfaces.
Your engine runs on air, fuel and spark. The spark is the center of it all, and for that we need electricity. Your battery supplies electricity, but only enough to get you a few miles down the road. We need more. That's where the alternator comes in. The alternator continually charges the battery so that we never have to worry about that whole "running out of juice" problem. Your battery is 12 volts, but to keep the battery 100% charged and run all of your car's electrical doo-dads at the same time, the alternator has an output of between 13.5 and 14.8 volts.
Antifreeze, also called coolant, is the colored fluid (usually green or red) found in your radiator. Antifreeze serves a few purposes. The most important and known is keeping the water in your radiator and engine from freezing in cold temps. It also keeps that same water from boiling over in the summer. Radiators are normally filled with a 50/50 mixture of antifreeze and water. The third function of antifreeze, or coolant is lubrication -- it lubricates the moving parts it comes in contact with, like the water pump.
Automatic transmission
A type of transmission that shifts itself (as opposed to manual transmission - also known as stick-shift). A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine. Newer automatics use electronic controls to regulate shifting and torque converter lockup.
The battery is a storehouse of electrical energy for starting the engine. All cars and light trucks today have a 12-volt battery. Most are also maintenance-free, meaning you don't have to add water to them periodically. Some even have built-in charge indicators to tell you if they need charging. A green dot in the window means the battery is at least 75% charged, no dot means it needs recharging, and a clear or yellow window means you need a new battery because the water level inside is low. Don't try to jump start or charge such a battery. You might be able to salvage the battery if you can pry the sealed caps open (some do unscrew) and add distilled water, 
but sometimes the battery must be replaced. Batteries are rated according to their Cold Cranking Amp (CCA) capacity. As a rule of thumb, an engine needs a minimum of one CCA for every cubic inch of displacement, and preferably two. The higher the CCA rating of the battery, the better. A typical passenger car battery might be rated at 500 CCA or higher.
Also called bellows, these are the protective rubber (synthetic or natural) or hard plastic (usually Hytrel) covers that surround CV joints. The boot's job is to keep grease in and dirt and water out. Split, torn or otherwise damaged boots should be replaced immediately. Old boots should never be reused when servicing a joint. Always install new boots.
Brake Bleeding
This is the process of removing air bubbles from the brake system by pumping fluid through the lines. Air bubbles are bad because they compress when pressure is applied resulting in a low or spongy feeling pedal. The correct procedure for bleeding the brakes on most RWD vehicles is to start at the furthest wheel. Do the right rear then left rear brake, followed by the right front and left front brakes. On a FWD vehicle with a diagonally-split brake system, do the right rear then left front brake, followed by the left rear and right front brake.
Brake Disc
Brake Drum
The basis of a drum brake system. It is a circular metal component that rotates with the road wheel. A set of brake shoes that are fixed in position and act on the drum by expanding.
Brake Pads
Brake Shoes
Brake Squeal
The annoying high-pitched screech that's sometimes heard when braking. A common ailment on many disc brake-equipped cars, it is caused by vibration between the brake pad and rotor. It causes no harm, but metallic scraping 
sounds should be investigated because it usually means the brake linings are worn down to their metal backing plates. If not replaced, the metal-to-metal contact can ruin the rotors or drums. Brake squeal can be eliminated by installing shims on the backs of brake pads.
The brake system uses hydraulic pressure to stop the vehicle when you step on the brake pedal. Pushing the pedal down pumps fluid from the master cylinder to the brakes at each wheel. This squeezes the brake linings against the rotors and drums, creating friction that brings the vehicle to a halt. The only maintenance the system requires is to check the fluid level periodically, and to replace the fluid every couple of years-or when brake repairs are performed.
A hydraulically activated device in a disc brake system, which is mounted straddling the brake rotor (disc). The calliper contains at least one piston and two brake pads. Hydraulic pressure on the piston(s) forces the pads against the rotor.
A shaft in the engine on which are the lobes (cams) that operate the valves. The camshaft is driven by the crankshaft, via a belt, chain or gears, at one half the crankshaft speed. One or more camshafts regulate the opening and closing of the valves in all piston engines.
Carbon Monoxide (CO)
A colourless, odourless gas given off as a normal byproduct of combustion. It is poisonous and extremely dangerous in confined areas, building up slowly to toxic 
levels without warning if adequate ventilation is not available.
A device, usually mounted on the intake manifold of an engine, which mixes the air and fuel in the proper proportion to allow even combustion.
Catalytic Convertor
A device installed in the exhaust system, like a muffler, that converts harmful by-products of combustion into carbon dioxide and water vapour by means of a heat-producing chemical reaction.
A device, usually a moveable valve, placed in the path of a carburettor to restrict the flow of air.
Clutch Pedal
The pedal to the left of the brake pedal on cars with manual transmissions that enables the driver to change gears.
Antifreeze, also called coolant, is the colored fluid (usually green or red) found in your radiator. Antifreeze serves a few purposes. The most important and known is keeping the water in your radiator and engine from freezing in cold temps. It also keeps that same water from boiling over in the summer. Radiators are normally filled with a 50/50 mixture of antifreeze and water. The third function of antifreeze, or coolant is lubrication -- it lubricates the moving parts it comes in contact with, like the water pump.
How Does It Work? The key chemical component in today's coolants is ethylene glycol. Mixed correctly, this stuff can keep your radiator fluid from freezing even if the temperature is less than 30 degrees below zero! That's cold. The amazing thing is that it can also keep the same fluid from boiling at as much as 275 degrees F. 
Antifreeze can really get control of those water molecules!
The main driving shaft of an engine that receives reciprocating motion from the pistons and converts it to rotary motion. Together, the crankshaft and the connecting rods transform the pistons' reciprocating motion into rotary motion.
In an engine, the round, straight-sided cavity in the engine block in which the piston(s) ride. Typically made of cast iron and formed as a part of the block.
Cylinder Block
Cylinder Head
The main structural member of an engine in which is found the cylinders, crankshaft and other principal parts.
Diesel Engine
Diesel Oil
A special gearbox designed so that the torque fed into it is split and delivered to two outputs that can turn at different speeds. Differentials within axles are designed to split torque evenly; however, when used between the front and rear axles in four-wheel-drive systems (a center differential), they can be designed to apportion torque unevenly.
A thin metal rod marked with level indicators that is inserted into the oil sump to determine how much oil is left in the engine. Dipsticks are also used to check transmission fluid.
Disc Brake
A hydraulic braking assembly consisting of a brake disc, or rotor, mounted on an axle, and a caliper assembly containing, usually two brake pads which are activated by hydraulic pressure. The pads are forced against the sides of the disc, creating friction that slows the vehicle. Disc brakes provide a more linear response and operate more efficiently at high temperatures and wet conditions than drum brakes.
Drive Shaft
The propeller shaft that transmits engine torque to the differential, or from the differential to the drive wheels. In front-wheel drive vehicles, the two drive shafts are often referred to as "half shafts."
Emergency Brake
A braking system that acts independently of the main hydraulic system and can slow or stop the car in the event that the primary system fails. It can also be used to keep the car from rolling on unleveled ground. Also called the "parking" or "hand" brake.
Electrical System
The battery, wires and electrically operated accessories in a vehicle. All modern passenger cars, light trucks and most large motorcycles have 12-volt electrical systems. Farm tractors, most small motorcycles, antique cars and pre-1967 Volkswagens have 6-volt electrical systems. Most heavy-duty trucks use 24-volt systems. The electrical system uses the battery and charging system as its power source, with wires and switches routing the voltage to where it's needed. The metal body serves as the ground or return path for the voltage back to the battery. The electrical system is protected against damage by various devices (See Circuit Breaker, Fuse and Relay). Most electrical problems fall into one of three basic categories: poor ground connections (loose or corroded), opens (breaks in circuit wires, connectors or switches), or shorts (grounded circuit wires or switches).
Electronic Control Unit (ECU)
The Electronic Control Unit (ECU) controls the fuel injection system, ignition timing, and the idle speed control system. The ECU also interrupts the operation of the air conditioning and EGR systems, and controls power to the fuel pump (through the control relay). The ECU consists of an 8-bit microprocessor, random access memory (RAM), read only memory (ROM), and an input/output interface. Based on information from the input sensors (engine coolant temperature, barometric pressure, air flow, etc.), the ECU determines optimum settings for the output actuators (injection, idle speed, ignition timing, etc.).
Electronic Fuel Injection
This type of system uses computer-controlled fuel injectors to spray fuel into the engine rather than mechanically controlled injectors or a carburettor.
EFI comes in several varieties: 

"throttle body injection" (TBI)
"multi-port injection" (MFI)
"sequential fuel Injection" (SFI)

Electronic fuel injection is considered to be superior to carburetion because it allows more precise fuel metering for easier starting, lower emissions, better fuel economy and performance.

Electronic Ignition
A system in which the timing and firing of the spark plugs is controlled by an electronic control unit, usually called a module. These systems have no points or condenser.
Emissions Control System
The by-product composed of spent fuel from combustion engines.
Exhaust Manifold
The network of passages that gathers the exhaust gases from the various exhaust ports and routes them toward the catalysts and mufflers of the exhaust system. A manifold with free-flowing passages of a carefully designed configuration, called a "header", can improve breathing.
Exhaust System
Fan Belt
A condition in which an excessive amount of fuel is delivered to the cylinders making starting the engine difficult or impossible.
Four-Wheel Drive (4WD)
A method of driving a vehicle by applying engine torque to all four wheels. Various schemes are used for 4WD including part-time, full-time and variable four-wheel drive. The primary advantage of four-wheel drive is increased 
traction-which is especially useful for off-road excursions or severe weather driving, but is of little practical value for normal driving. Because of the added friction in the drivetrain, a four-wheel drive vehicle typically gets significantly lower fuel mileage than a front- or rear-wheel drive vehicle. To help cut the drag, most 4WD drivetrains have a transfer case that allows the driver to select either two- or four-wheel drive depending on driving conditions. In trucks, you'll often find locking hubs on the front wheels that can be locked in the "on" or free-wheeling position as needed. Some performance cars have full-time variable four-wheel drive and use a computer-controlled transfer case to route power between the wheels.
Front Wheel Drive
A vehicle that is propelled by its front wheels rather than being pushed by its rear 
Fuel Economy
The number of litres of fuel used per 100 kms of driving.
Fuel Filter
A device that filters impurities from the fuel before it reaches the carburettor. Usually located near the carburettor in the fuel line coming from the fuel pump or inside the carburettor or fuel pump itself.
Fuel injector
The fuel injector is the last stop for fuel in your engine before it goes boom inside the combustion chamber. It is basically an electrically operated gate that opens just long enough to meter the perfect amount of fuel to run the engine. On one end of the gate is the cylinder where the gas is ignited, and on the other end is a whole bunch of gas under high pressure. When your car's brain (connected to a Mass Airflow Meter or MAF to take measurements) sends an electrical impulse to the injector, it opens the gate for an short burst of fuel.
A protective device in a circuit that prevents circuit overload by breaking the circuit when a specific amperage is present. The device is constructed around a strip or wire of a lower amperage rating than the circuit it is designed to protect. When an amperage higher than that stamped on the fuse is present in the circuit, the strip or wire melts, opening the circuit.