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Oil

1. A diesel fuel. 2. A liquid lubricant used to reduce friction between moving parts.

Oil Bath Filter

An engine air filter that channels the air through an oil bath that traps duct and debris.

Oil Bleed Line

An external line that usually bypasses a metering device to ensure positive oil return to the compressor at all times.

Oil Bleed Passage

Internal orifice that bypasses a metering device to ensure a positive oil return to the compressor.

Oil Burner

1. A diesel. 2. An older car or truck that uses excessive oil, generally evident by a smoking exhaust.

Oil Canning

A sheet-metal panel popping from convex to concave and/or vice versa.

Oil Clearance

The small space between the main bearing and crankshaft journal, usually 0.0001 to 0.003 inch (0.025 to 0.076 mm), for lubricating oil to circulate.

Oil Control Ring

The bottom piston ring that scrapes oil from the cylinder wall.

Oil Cooled Piston

A piston that is cooled by a jet of oil sprayed under the dome of some diesel-and endurance-race engines.

Oil Cooler

1. A device used to cool oil or automatic transmission fluid. 2. A device used to cool race-car manual transmission and final-drive lubricants.

Oil Dilution

The thinning of oil in the crankcase, usually caused by gasoline seepage past the piston rings from the combustion chamber.

Oil Dipper

A small scoop located at the bottom of the connecting rod in early, low-performance engines to dip into the oil to lubricate the rod bearings crankshaft.

Oil Filter

A component, located near the oil pump, that removes abrasive particles from the motor oil by a straining process as the oil circulates through the lubrication system.

Oil Gallery

Passages drilled or cast into the cylinder heads, engine block, and crankshaft to receive pressurized oil from the oil pump for distribution throughout the engine.

Oil Injector

A term used for oil-injection cylinder.

Oil Level Indicator

A term used for dipstick.

Oil Pan

A removable part of the engine that contains the oil supply.

Oil Pressure

The pressure, 15 to 75 psi (103 to 517 kPa), developed by the oil pump to force oil through the lubrication system.

Oil Pump

A pump, driven directly or indirectly by the camshaft, that draws oil from the oil pan and forces it, under pressure, through the engine lubrication system.

Oil Pumping

The leakage of oil past the rings and into the combustion chamber.