An engine oil leak may develop from the oil pump drive O-ring. This can often be confused with an intake manifold gasket leak. Careful inspection is required to determine the exact cause of the leak. Replacement of the failed 0-ring will commonly correct this concern.
Car Problem Reports
Chevrolet Lumina Oil Pump Drive O-Ring May Leak Oil
Chevrolet Lumina Problem
Engines Affected: 3.1L V6, 3.4L V6
Average Mileage: 125,333 mi (86,000 mi - 150,000 mi)
Visitor, 1993 Chevrolet Lumina, 3.1L V6, 86,000 mi
Thought at first it was the intake end gasket but actually it was the oil pump drive o-ring. Was able to pull up the drive shaft enough to clean and get some ultra copper gasket maker on the bottom of the shoulder of the shaft.
Visitor, 1995 Chevrolet Lumina, 3.1L V6, 150,000 mi
oil leaking from the o ring