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Rad

A term often used to describe a radically modified engine or vehicle.

Radial Compressor

A space-saving compressor used on small cars.

Radial Grid

A lead alloy framework for the active materials of a lead acid battery that has radial support spokes to add strength and improve continuity.

Radial Motion

A motion extended to either, or both, extremes of a radius.

Radial Ply

A term used for radial ply belted tire.

Radial Ply Belted Tire

A tire having the ply cords placed at right angles tot he beads, plus belts under the tread section providing the least tread distortion while moving, thereby minimizing tread wear and rolling friction.

Radial Runout

Variations in tire diameter; the measured amount of out-of-roundness on rotating tires.

Radial Tire Waddle

A term used for tire waddle.

Radiation

1. A natural process by which energy is transmitted. 2. The transfer of heat through a soled, liquid, or gas medium.

Radiation Dose

The amount of energy per unit of mass of material deposited at each point of an object undergoing radiation.

Radiator

A heat exchanger used to remove heat from the coolant in the cooling system containing a vertical- or horizontal-finned tubing section connected between two tanks.

Radiator Cap

A term used for radiator pressure cap.

Radiator Core

The center of the radiator, made of tubes and fins, used to transfer heat from the coolant to the air.

Radiator Fan

A term used for fan.

Radiator Hose

An oil- and ozone-resistant synthetic-rubber hose that connects the radiator to the thermostat outlet housing and water pump inlet housing.

Radiator Hose Clamp

A term used for hose clamp.

Radiator Pressure Cap

A cap that seals in pressure from hot expanding coolant until a predetermined limit is reached, then the valve opens, allowing excess pressure to escape, generally to a coolant-recovery tank.

Radiator Shutter System

An engine temperature-control system that controls the amount of air flowing through the radiator by use of a shutter system.

Radio Choke

A small coil of wire installed in the power lead leading to a pulsing unit such as an IVR to prevent radio noise ( reduce RFI).

Radio Frequency Interference

(RFI) A form of electromagnetic interference created in the ignition secondary circuit which disrupts radio and television transmission.