Glossary “heat affected zone” Definition:
A metal area that has been heated beyond its critical temperature, causing it to lose strength.
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heat control valve
Glossary “heat control valve” Definition:
Thermostatically controlled valve in the exhaust manifold to divert heat to the intake manifold before the engine reaches normal operating temperature.
heat crayons
Glossary “heat crayons” Definition:
Used to determine the temperature of the aluminum or other metal being heated. They will melt at a specific temperature and warn you to prevent overheating.
heat dam
Glossary “heat dam” Definition:
Narrow groove cut into the top of the piston. It restricts the flow of heat down into the piston.
heat
Glossary “heat” Definition:
1). Form of energy released by the burning of fuel. 2). Any temperature above absolute zero.
heads up display (HUD)
Glossary “heads up display (HUD)” Definition:
The images of a vehicle’s instrument panel, displayed on the inside surface of the windshield in front of the driver where they can seen without taking the eyes off the road.
health hazard
Glossary “health hazard” Definition:
Anything which can have a harmful effect on health under the conditions in which it is used or produced.
headliner
Glossary “headliner” Definition:
Part of the automobile-interior overhead or the covering of the roof inside.
headrest
Glossary “headrest” Definition:
Padded frame that fits at the top of the seat back.
headrest guide
Glossary “headrest guide” Definition:
The sleeve that accepts the headrest post and mounts in the seat back.
header tank
Glossary “header tank” Definition:
The top and bottom tanks or side tanks of a radiator in which coolant accumulates or is received.
headlamps
Glossary “headlamps” Definition:
Lights at the front of a vehicle used to illuminate the road ahead. Also known as headlights.
headlight aimers
Glossary “headlight aimers” Definition:
Equipment used to adjust the direction of thevehicle headlights.
headlight aiming screws
Glossary “headlight aiming screws” Definition:
Screw with a special plastic adapter mounted to it. The adapters fit into the light assembly, and are used to adjust the horizontal and vertical planes of the headlights.
headlight delay
Glossary “headlight delay” Definition:
System that turns off the headlamps automatically after the operator leaves the vehicle, though the lights were left in the on position.
headlights
Glossary “headlights” Definition:
Term used for headlamps.
headache rack
Glossary “headache rack” Definition:
A rack that is provided at the rear of a truck-cab interior to prevent a load from crashing through the rear window.
header
Glossary “header” Definition:
Free flowing exhaust manifold used on high-performance cars.
head on view
Glossary “head on view” Definition:
Compares the test panel to the vehicle straight on , or perpendicular. Also refers to a reference point to determine front end alignment angles.
head pressure
Glossary “head pressure” Definition:
Pressure of the refrigerant from the discharge valve through the lines and condenser to the metering-device inlet.