Full pressure lubrication, through a full-flow oil filter is supplied by a gear-type oil pump. Oil is
drawn up through the oil pump screen and passes through the pump to the oil filter. The oil
filter is a full-flow paper element unit with an anti-drain back valve. An oil filter bypass valve is
used to ensure adequate oil supply, in the event the filter becomes plugged or develops
excessive pressure drop. Filtered oil flows into the main gallery and then to the camshaft, the
balance shaft, the rear bearing, and the crankshaft bearings.
The valve lifter oil gallery supplies oil to the valve lifters. Oil flows from the valve lifters
through the hollow valve pushrods to the valve rocker arms. Oil drains back to the crankcase
through the oil drain holes in the cylinder head. The camshaft timing chain is drip fed from
the front camshaft bearing. The pistons and piston pins are lubricated by oil splash.
Chevy 4.3L Vortec Engine Oiling System