Glossary “urethane adhesive” Definition:
Any of several strong polymer adhesives that are used to intall auto glass. Urethane adhesives are necessary to meet federal standards for windshield retention in most late model passenger vehicles.
upstream blower
Glossary “upstream blower” Definition:
Blower arranged in the duct system so as to push air through the heater and/or A/C core(s).
upstream
Glossary “upstream” Definition:
Secondary air flow sent by the AIRD to ports in the exhaust manifold. Also refers to placement of oxygen sensors that are upstream (ahead of) the catalytic converter. Also see downstream.
upshift
Glossary “upshift” Definition:
Shifting from a lower gear to a higher gear ratio.
UPS
Glossary “UPS” Definition:
Uninterruptible Power Supply; a power supply that includes a battery to maintain power in the event of a power outage.
upr
Glossary “upr” Definition:
Acronym form of Upper.
upper radiator hose
Glossary “upper radiator hose” Definition:
Radiator hose from the engine coolant outlet to the radiator inlet.
upper end
Glossary “upper end” Definition:
Parts of the engine that include cylinder heads and valvetrain.
upper control arm
Glossary “upper control arm” Definition:
Front suspension component bolted to the frame between the pivoting attachment point on the vehicle-frame crossmember and the upper ball joint, which is fastened to its outer end having bushings that are attached to the control arm.
upper A-arm
Glossary “upper A-arm” Definition:
Term used for upper-control arm.
updraft carburetor
Glossary “updraft carburetor” Definition:
Carburetor having an updraft airflow.
updraft
Glossary “updraft” Definition:
Device or system having an upward airflow.
unsprung weight
Glossary “unsprung weight” Definition:
Vehicle weight not supported by the springs, including the steering knuckle, brake assembly, tire and wheel.
unscheduled deployment
Glossary “unscheduled deployment” Definition:
Term used when referring to air bag system that could be set off without the vehicle being involved in a crash.
unobtainium
Glossary “unobtainium” Definition:
A mythical alloy that is lighter, stronger, more flexible and, at the same time, more rigid than anything available. Also refers to any part that is unobtainable.
unloading solenoid
Glossary “unloading solenoid” Definition:
Electrically controlled valve for operating the throttling valve or bypass valve in some applications.
unloader
Glossary “unloader” Definition:
Device linked to the throttle valve to open the choke valve when in the wide-open throttle position.
unloaded caliper
Glossary “unloaded caliper” Definition:
Bare rebuilt caliper with no pads or hardware.
unlined clutches
Glossary “unlined clutches” Definition:
Steel clutches which feature no lining. See clutches.
unleaded gasoline
Glossary “unleaded gasoline” Definition:
Gasoline that contains less than 0.0018 ounces (0.05 grams) of lead per gallon (3.785 liters).