Engine - Oil Leak At Rear Of Crankshaft

Information:IB05-01-S006

Diagnostic Information On Engine Oil Leak From Rear Of Crankshaft

ISSUE DATE: AUGUST 30, 2005

Affected Vehicles:
2005 Isuzu Ascender with 4.2L Engine

Service Information

This bulletin is being published to aid technicians in the diagnosis of an engine oil leak from the rear of the engine. Misdiagnosis of the engine oil leak will lead to repeat engine crankshaft rear main oil seal replacements.

Porosity in the rear crankshaft pilot bore area may be the cause. This condition became evident when a new cross-drilled crankshaft oil passage was implemented. This porosity may not be visible and you may not be able to feel any imperfections in the pilot bore machining.





Perform normal diagnostics. Refer to Oil Leak Diagnosis in the Service Manual. If the Oil Leak Diagnosis indicates that the oil is leaking from the rear of the crankshaft pilot bore area, then inspect the pilot bore area of the rear crankshaft flange for oil. Refer to above illustration. If oil is present, the oil leak may be due to crankshaft porosity. To repair this concern, replace the engine crankshaft per published service procedures. If no oil is found, continue with Oil Leak Diagnosis.





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