Possible Leakage Points

Examine the following areas for oil leakage.

Underhood

• Rocker cover sealant
• Intake manifold gaskets
• Cylinder head gaskets
• Oil filter
• Distributor O-ring
• Oil level indicator (dipstick) tube connection
• Oil pressure sending unit
• Cup plugs and/or pipe plugs at end of oil passages

Under Engine—With Vehicle on Hoist

• Oil pan gasket
• Oil pan front and rear end seals
• Crankshaft front seal
• Crankshaft rear seal

With Transmission and Flywheel Removed

• Crankshaft rear seal

Air leakage in area around a crankshaft rear oil seal does not necessarily indicate a rear seal leak. However, if no other cause can be found for oil leakage, it can be assumed that rear seal is the cause of the oil leakage.

• Rear main bearing cap parting line.
• Rear main bearing cap and seals.
• Flywheel mounting bolt holes.
• Rear cup plugs and or pipe plugs at the end of oil passages.

Oil leaks at crimped seams in sheet metal parts and cracks in cast or stamped parts can be detected when pressurizing the crankcase.

NOTE: Light foaming equally around rocker arm cover bolts and crankshaft seals is not detrimental and no corrections are required in such cases.