GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Low oil pressure

    • Perform an oil pressure test.
    • Repair or replace as required.

Improper lubrication to the valve train

Inspect the following components, and repair or replace as required:

    • Restricted oil filter
    • The valve lifter
    • The valve lifter bore
    • The oil filter bypass valve
    • The oil pump and pump screen
    • The engine block oil galleries

Broken valve spring

Replace the valve spring.

Worn or damaged valve lifter bore

Repair or replace as required.

Worn or dirty valve lifters

Replace the valve lifters.

Stretched or broken timing chain and/or damaged sprocket teeth

Replace the timing chain and sprockets.

Worn engine camshaft lobes

    • Inspect the engine camshaft lobes.
    • Replace the camshaft and valve lifters as required.

Worn valve guides or valve stems

Inspect the following components, and repair as required:

    • The valves
    • The valve guides

Stuck Valves

Carbon on the valve stem or valve seat may cause the valve to stay open

Inspect the following components, and repair as required:

    • The valves
    • The valve guides