Glossary
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V |W | X | Y | Z |
A
Accumulator reservoir that stores fluid or gas under pressure
Actuator device that moves as a result of an electrical signal
Aftermarket related to servicing or replacement
Air injection pollution control system that reduces hydrocarbon and carbon monoxide emissions by injecting air into the exhaust ports for more complete combustion
Anchor pin drum brake component that holds the secondary shoe in place when brakes are activated
Anti-oxidation additive chemical that reduces a liquid's ability to absorb oxygen and thicken
Anti-seize compound chemical that prevents two parts from rusting together
B
Backing plate round, metal plate that holds drum brake components in place
Baffle metal plate that interferes with the flow of exhaust gas to reduce noise
Ball socket connection that permits part movement in multiple directions
Band coarsely-lined, metallic strap, in an automatic transmission, that tightens to stop the rotation of a planetary gearset
Bearing(s) friction-reducing component that surrounds a spinning part
Bezel retaining ring that holds a stationary component in place
Bleeder screw screw that releases air from the hydraulic brake system
Blowby gases exhaust gases, containing harmful contaminants, that escape past piston rings and into the crankcase and oil pan
Blower motor fan that forces air from a heating and air conditioning system
Breaker point(s) contact switches, which help step up battery voltage, within the distributor
Bridge claw metal tabs of a wiper blade arm that hold the rubber blade insert in place
Bypass device that permits fluid to flow around, rather than through, a component
C
Caliper disc brake assembly that permits the piston and brake shoes to impart a clamping action on a revolving rotor, thereby stopping the attached wheel
Camshaft shaft containing cams, or lobes, that synchronizes valve operation with piston movement inside the engine cylinder
Centrifugal force outward force experienced by a rotating object
Chamois a soft, highly absorbent leather
Choke a plate at the carburetor opening that assists in cold-starting by constricting air flow and therefore making the fuel/air mixture richer
Circuit breaker electrical safety device, which can be reset, that breaks a circuit in the event of an electrical surge or short circuit
Clutch pack series of steel plates and friction discs, found in a differential, that prevents wheel lockup
Cold enrichment system fuel injection components that assist in cold-starting
Combination valve brake system component that acts as both a metering valve and a proportioning valve
Compression process of squeezing into a smaller space
Compression ratio ratio of internal cylinder volumes with the piston at maximum downward and upward positions
Compressor belt-driven pump that pressurizes a gaseous refrigerant and forces it through the air conditioning system
Compressor clutch magnetically engaged friction device that operates the compressor
Computer control central electronic apparatus that coordinates and manages numerous engine and vehicle operations
Condenser in distributors with breaker points, a device that stores electrical charge to prevent arcing; in air conditioning systems, a component that converts refrigerant from a gas to a liquid, thereby releasing its heat
Connecting rod metal arm that connects the piston to the crankshaft
Control arm pivoting lever that connects the vehicle frame to the steering knuckle and therefore wheel
Control assembly rod or cable and associated linkages that operate the parking brake cable
Control valve device for regulating the flow of liquid or gas through an opening
Convex outwardly curved
Core plug a.k.a. freeze plug; safety device to prevent frozen coolant from potentially cracking engine block
Countershaft geared shaft that transfers rotary motion from the transmission input shaft to the output shaft
Coupling connection
Cowl front portion of car body to which windshield is attached
Crankshaft irregularly-shaped shaft that converts up and down piston movement into rotary motion
Cylinder engine chamber in which piston moves and combustion takes place
Cylinder head engine block attachment that includes valves and associated components
D
Damper flap-like valve that regulates the flow of additional warm air into the engine
Dielectric compound silicone-based substance that prevents contamination of electrical connections due to salt, moisture, dirt, or corrosion
Diode electrical component that allows current flow in only one direction; used to convert AC (alternating current) to DC (direct current)
Distributor advance mechanism that adjusts spark plug operation with engine speed to promote complete combustion
Draincock T-shaped, threaded plug used to drain the radiator
Drive shaft metal shaft that transmits rotary motion from the transmission to the differential
Dry refill capacity refill capacity if reservoir could be completely drained
Dry steering turning the steering wheel while vehicle is motionless
Dwell angle amount of distributor rotation while the breaker points remain closed to build up voltage
Dynamic balance balanced about the center of rotation and from side-to-side using a tire spinning machine
E
Electrode exposed metal conductor through which current flows in a spark plug
Electrolyte mixture of distilled water and sulfuric acid found in batteries
Electronic fuel injection fuel management system where pressurized fuel injectors are electronically controlled
Electronic ignition ignition system that utilizes electronic circuitry instead of conventional breaker points to build up and distribute voltage
Emission control any of several pollution control devices associated with the fuel or exhaust systems
Engine block basic structural element of an engine that contains the pistons and to which other components are attached
Engine vacuum suction created at the intake manifold due to piston movement
Ethylene glycol active ingredient in antifreeze
Evaporator air conditioning system device that converts refrigerant from a liquid to a gas, thereby causing it to absorb heat and create cooling action
Exhaust manifold series of metal tubes that connects the engine exhaust ports to a singular exhaust pipe
Expansion valve air conditioning system device that reduces pressure in the liquid refrigerant before it enters the evaporator
F
Fan shroud plastic enclosure, situated around the cooling fan, that directs air flow through the radiator
Feed wire device providing main electrical supply
Filament fine wire, which glows when conducting current, found inside of a bulb
Firewall heat protective barrier between the engine and passenger compartments
Fitting portion of a component to which another is connected
Flame front moving boundary of a fuel/air mixture explosion
Flange specially formed edge used to join parts
Flare nut wrench a.k.a. tubing wrench; box wrench with nearly closed end to permit firm grasp of a fitting nut and reduce chance of stripping it
Flasher electrical switch that repeatedly opens and closes a circuit, thereby producing continuous on and off action
Float component which controls flow of fuel entering a carburetor
Flooded condition where excess unburned fuel has accumulated in the intake manifold, engine cylinders or carburetor
Fluid clutch device that transfers rotary motion through use of a fluid
Flywheel large, heavy disc, at rear of crankshaft, that smoothes out power pulses from the engine
Friction disc clutch component that transmits rotary motion from the flywheel to the transmission input shaft
Fuel pressure regulator fuel injected system device that controls pressure at the fuel injector tips
Fuel/air mixture combustible combination of air and vaporized gasoline
G
Gasket sealing membrane that prevents fluid or gas leakage between two fixed parts
Glow plug diesel engine heating device that assists in cold starts
Governor apparatus that limits engine speed
Grease cap dome-shaped cover that prevents contamination of wheel bearings
Grommet eyelet made of firm material to protect an opening in a part surface
Ground connection to a large, metal object, such as the body or frame, that acts as a common return point in an electrical circuit
H
Half shaft short drive axle used in front-wheel drive vehicles
Halogen bulb halogen gas-filled bulb that burns brighter than an ordinary incandescent bulb
Harmonic balancer circular weight attached to the front of the crankshaft to reduce rotational vibration
Heat riser a.k.a. exhaust manifold heat valve; valve that permits redirected exhaust gases to heat the intake manifold bottom, thereby quickening engine warm-up
Heat shield protective covering over catalytic converter that prevent burns
Heat stove metal shroud placed over the exhaust manifold to generate preheated air for the engine intake
Heater control valve vacuum-controlled device that regulates the flow of coolant into the heater core
Heater core a.k.a. water heater; miniature, radiator-like device that releases heat, absorbed by the coolant, into the passenger compartment
Hex head a.k.a. Allen socket; bolt head with six-sided indentation that requires similarly shaped tool to tighten or loosen
Hub central portion of a rotating disc or pulley
Hydraulic failure total breakdown of fluid-operated system
Hydrometer device that measures fluid density and interprets fluid condition
I
Idle mixture appropriate fuel/air mixture at idle speed
Idle speed engine speed without application of accelerator
Idler arm steering linkage component, mounted on the vehicle frame, that supports the center link and tie rods
Idler pulley pulley that does not drive a component but modifies belt routing instead
Ignition coil electrical component (transformer) that increases battery voltage tremendously to operate the spark plugs
Ignition timing relationship of spark plug operation to piston movement
Impact load sudden force
Impeller rotating, fan-like device that pumps fluid
Inboard toward the center of the vehicle
Injection timing relationship of piston movement to the injection of fuel in the engine cylinder
Injector coil electrical device that controls fuel pulsation from the fuel injectors
Inlet heater hose small diameter, rubber hose that carries coolant into the heater core
Intake manifold central reservoir that guides air or fuel/air mixture into the engine cylinders
J
Jet narrow opening that controls fuel consumption in a carburetor
Journal highly machined section of crankshaft around which it rotates or to which connecting rods are attached
K
Kickdown apparatus that causes an automatic transmission to downshift for fast acceleration when the accelerator pedal is floored
L
Lash the clearance between the valve stem and rocker arm when the valve is closed; in gears, the amount of free play
Lifter a.k.a. tappet; cylindrical metal device that converts the rotary motion of camshaft lobe into linear push rod motion
Lining frictional contact component of a drum brake
Lobe egg-shaped bump on camshaft
Locating pins guide pin that controls disc brake caliper movement
Lock tab metal clip that locks a removable component in place
Lug nut and bolt fastener that attaches tire/wheel assembly to the vehicle
M
Machining a.k.a. turning; grinding to an extremely smooth surface
Master cylinder piston-operated pump that pressurizes fluid in the brake system, thereby activating the brakes
Metering valve brake system component that ensures simultaneous application of disc and drum brakes when the brake pedal is depressed
N
Neutral safety switch automatic transmission device that prevents the engine from being started if the transmission is not in neutral or park
Noise suppressor device (capacitor) that smoothes electrical system voltages, thereby reducing radio interference
Normally aspirated using uncompressed air, that is, not turbocharged or supercharged
O
O-ring compressible rubber gasket, located in a groove and typically coated with fluid, that deforms slightly to form a tight seal
Operating temperature stabilized coolant temperature during normal engine operation
Outboard toward the outside of a vehicle
Outlet heater hose small diameter rubber hose that carries coolant away from the heater core
Overrunning clutch clutch that operates in only one direction
Oxidize process through which a substance absorbs and combines with oxygen
Oxygen sensor a.k.a. exhaust gas sensor; emission control that monitors the oxygen content of exhaust gas so the computer control can make fuel/air mixture adjustments
P
Pad disc brake frictional contact component typically made of a metallic or organic compound
Phillips head screw with X-shaped groove in head
Pilot bearing clutch component that supports the front of the transmission input shaft inside the rear of the crankshaft
Pinion gear small gear that drives a larger gear at slower speed; for example, the starting motor gear rotates a flywheel to start the engine
Piston cylindrical-shaped metal head that moves with expanding or contracting gas or fluid
Piston ring seal that provides tight clearance between a piston and cylinder wall
Pitman arm metal shaft that converts rotary motion of steering gear box output shaft to linear motion of the steering linkage
Planetary gear complex automatic transmission gear assembly where small (planet) gears rotate around a large, central (sun) gear
Plasticizer chemical additive that makes a material more flexible
Ply a.k.a. inner cord; flexible, fibrous membrane that provides tire with structural support
Point gap clearance between the two fully opened breaker points in a conventional ignition system
Polarity relationship between negative and positive terminals or poles
Port fuel injection a.k.a. multi-point fuel injection; fuel delivery system where each engine cylinder's intake port has a separate fuel injector
Pressure check valve device that permits fluid flow in one direction, thereby keeping the system free of air or contaminants
Pressure control valve apparatus that directs fluid flow in a power steering system
Pressure plate clutch component that engages or disengages the friction disc and flywheel
Primary shoe drum brake shoe facing the front of vehicle; usually smaller than the secondary shoe
Proportioning valve brake system device that equalizes disc brake and drum brake stopping power, thereby preventing rear tire skidding in quick stops
Push rod small, metal shaft that transfers linear motion from the lifter to the rocker arm; in a brake system, the shaft connecting the brake pedal with the master cylinder piston
R
Receiver-drier air conditioning system device that accumulates excess refrigerant and removes moisture
Refrigerant air conditioning system chemical that absorbs and releases heat
Relay electromagnetic switch that opens or closes a circuit
Release fork clutch component that forces the pressure plate into the friction disc, thereby engaging flywheel
Release lever component, attached to the clutch pedal by a cable, that activates the release fork and initiates clutch action
Resonator tubular exhaust system device that absorbs exhaust gas pulsation, thereby reducing noise
Rheostat electrical device with adjustable resistance
Ring gear in a transmission, the toothed circumference of a flywheel; in a differential, the large gear driven by the pinion gear
Rocker arm small, pivoting lever that operates the engine exhaust or intake valves
Rolling resistance natural tendency of loaded tire to resist flexure and therefore rotational movement
Runout warp in a disc-shaped object that causes wobble while spinning or prevents it from laying perfectly flat
S
Seal collar that prevents fluid or gas leakage between moving parts
Sealing bead a.k.a. fitting flange; ring-like protrusion on fitting, which provides a tight interior seal with attached hose
Seating wearing in such a way, from first use, that the two friction surfaces perfectly match
Secondary shoe drum brake shoe facing the rear of vehicle; usually larger than the primary shoe
Self-adjuster drum brake mechanism that maintains a constant gap between the drum and lining surfaces as the linings wear
Sending unit mechanical sensing device that observes a given condition and transmits an electrical signal to a dashboard gauge
Service valve air conditioning system access point that allows refrigerant maintenance activities
Servo small device that assists in the operation of a larger apparatus
Shift fork pronged, manual transmission device that engages a synchronizer to change gears
Shimmy side-to-side wheel wobble caused by dynamic imbalance
Sight glass transparent view port that permits observation of a liquid or gas condition
Sludge gel-like oil formations caused by contaminants
Solenoid magnetic plunger switch that controls the operation of another device
Spark plug socket special wrench socket that completely fits over an exposed spark plug and has a rubber insert to grasp the spark plug terminal for removal
Specific gravity the density of a fluid relative to water
Spider gear small, beveled gear that drives a rear axle
Spindle short, metal shaft on which wheel bearing rotates and supports wheel
Spline parallel ridges on a shaft surface that allow any attached component sliding, but not rotational, motion
Stabilizer bar a.k.a. sway bar; metal rod that connects control arms, thereby reducing body lean in turns
Star wheel main component of the drum brake self-adjuster
Starter drive output shaft of starter motor
Static balance balanced about the center of rotation (but not side-to-side) using a bubble balance
Steering arm stop pads cushions that prevent excessive steering linkage movement
Steering knuckle apparatus that has a spindle and connects the wheel to remainder of suspension system through the ball joints
Steering shaft metal rod that transfers rotary motion from the steering wheel to the steering gear
Striker bolt and plate rod and latch mechanism used to secure door, trunk or hood
Strut rod metal shaft, attached to vehicle frame, that limits lower control arm movement
Supercharged intake system modified to ingest additional air from a belt-driven air pump and therefore produce more engine power
Synchronizer manual transmission component that prevents gear grinding during shifts
T
T-fitting T-shaped device that connects three hoses
Temperature sensor device for measuring engine coolant or air intake temperature so computer control can adjust fuel/air mixture
Terminal metal stub that serves as electrical connection
Thermostatic control air conditioning system device that turns off compressor when evaporator becomes too cold
Throttle body portion of air intake system that contains the throttle and is connected to the intake manifold
Throttle linkage series of rods and pivot mechanisms that operates the throttle
Throttle position sensor (TPS) electrical device (rheostat) that helps the computer control continuously adjust the fuel/air mixture
Throttle valve flap-like device, connected indirectly to the accelerator pedal, that controls the flow of air into the engine
Timing belt cogged, or toothed, belt that transfers rotary motion from the crankshaft to the camshaft
Timing gear either of two matched gears located on the front ends of the crankshaft and camshaft
Tire/wheel assembly tire and wheel combination as one unit
Torque rotational or twisting effort
Torque converter component (fluid clutch) that engages or disengages the engine and automatic transmission
Torque wrench special tool that measures the tightness of a nut or bolt; prevents excessive tightening that damages parts or inadequate tightening that permits part failure
Torx head screw head with a star-shaped indentation that requires similarly shaped tool to tighten or loosen
Tower distributor cap projection that passes current from the underlying rotor to the attached spark plug wire
Transaxle component, commonly found in front-wheel drive cars, that acts as both a transmission and differential
Transmission pan lower portion of transmission that serves as a fluid reservoir
Transmission shift linkage series of rods and pivot mechanisms that connects the shift lever to the transmission
Turbocharged intake system modified to ingest additional air from an exhaust-driven air pump and therefore produce more engine power
V
Vacuum modulator automatic transmission component that controls shifting action based upon engine load
Vacuum motor a.k.a. vacuum diaphragm; temperature-controlled air cleaner attachment that operates an air flow valve
Valve component that controls the flow of fuel/air mixture into, or exhaust gas from, the engine cylinder
Valve body bottom portion of automatic transmission that contains numerous valves and fluid controls
Valve core spring-operated valve, contained inside valve stem, that controls tire inflation and deflation
Valve cover cylinder head covering that encloses the valves and associated components
Valve train interconnected components that operate the engine valves
Vapor lock stoppage of fluid flow due to formation of bubbles caused by high temperature or low pressure
Volatility a measure of the ease with which a liquid vaporizes or evaporates
Voltage leak unintended passage of electrical current through conductor or defective insulator
W
Water jacket engine block and cylinder head cavities through which coolant circulates to absorb heat
Wheel cylinder drum brake component that contains fluid and activates the brake shoes
Wheel rim width depth between interior edges of wheel, or approximate height of wheel when laid on its face
Wire feeler gauge tool, composed of a series of short wires of known diameter, that is used to measure small gaps
Y
Yoke broad, U-shaped support, located at end of a shaft, that is a portion of the universal joint
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