Engine Lubrication: Description and Operation

Engine Lubrication System






The lubrication system is a full flow filtration pressure feed type. The oil pump is mounted in the timing chain cover and is driven by the crankshaft

Oil - arrows - from the oil pan (10) is pumped by a internal gear type oil pump (6) directly coupled to the crankshaft. The pressure is regulated by a relief valve located in the timing chain cover. The oil is pumped through an oil filter and feeds a main oil gallery. This oil gallery feeds oil under pressure to the main and rod bearings, camshaft bearings. Passages in the cylinder block feed oil to the hydraulic lifters and rocker shaft (3) brackets which feeds the rocker arm pivots (1).

The oil pump (6) is located in the timing chain cover. It is driven by the crankshaft.

An engine oil cooler is used on 3.8L engines (heavy duty cooling only). The cooler is a coolant to oil type and mounted between the oil filter and engine block.

Engine oil travels from the oil filter and into the oil cooler. Engine oil then exits the cooler into the main gallery. Engine coolant flows into the cooler from the heater return tube and exits into the water pump inlet.

The engine oil pressure switch is located on the lower left front side of the engine. It screws into the oil filter adapter. The normally closed switch provides an input through a single wire to the low pressure indicator light on the instrument cluster.

The oil pressure switch provides a ground for the instrument cluster low oil pressure indicator light. The switch receives oil pressure input from the engine main oil gallery. When engine oil pressure is greater than 27.5 Kpa (4 psi), the switch contacts open, providing a open circuit to the low pressure indicator light.