For 1990-2009 cars

The engine's oil pump is located in the front timing cover and is driven by flats on the crankshaft timing sprocket. Oil is pulled from the oil pan into the gerotor pump. The pump forces oil under pressure to the oil filter. A regulator valve mounted in the front cover oil outlet regulates oil pressure and vents excess back to the inlet side of the oil pump.

Oil enters the filter and is routed through the main oil gallery in the engine cylinder block. The engine oil filter has both an anti-drainback valve and a by-pass valve. The anti-drainback valve prevents oil from draining out of the engine's oil galleries when it is not running and the by-pass valve allows oil to by-pass or flow around the filter's paper element if it should become plugged.

Engine oil leaving the pump flows through the cylinder block main oil gallery and is pressure fed to the main and connecting rod bearings. Oil also flows to the cylinder head and lubricates the camshaft, hydraulic lifters, and rocker arm. Run off oil from the cylinder head lubricates the timing gears and chain. Oil is also pumped from the main oil gallery to the hydraulic chain tensioner. Engine oil pressure and a ratchet mechanism in the tensioner are used to keep the timing chain tight.