Lubrication System

The engine lubrication system operates as follows:

• Oil is drawn into the oil pump through the oil pump screen cover and tube in the sump of the oil pan.
• On two-wheel and four-wheel drive vehicles, oil is pumped through the oil bypass filter on the left front side of the cylinder block.
• Oil enters the main oil gallery where it is distributed to the crankshaft main journals and to both cylinder heads.
• From the main journals, the oil is routed through cross-drilled passages in the crankshaft to lubricate the connecting rod bearings. Controlled leakage through the crankshaft main bearings and connecting rod bearings is slung radially outward to cool and lubricate the cylinder walls as well as the entire connecting rod, piston and piston rings assembly.
• The left cylinder head is fed from a drilling into the supply passage feeding the main gallery at the front of the cylinder block. The right cylinder head is fed from a drilling into the rear of the main gallery. Main gallery pressure is reduced as it enters the cylinder head galleries through fixed serviceable orifices located at the upper part of the feed passages. It is this reduced pressure in the cylinder head galleries which feeds the camshaft journals, the hydraulic lash adjusters and the primary and secondary timing chain tensioners.
• The camshaft lobe and roller followers are lubricated by splash created through valve train operation.