GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Low oil pressure

    • Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing .
    • Repair or replace as required.

Improper lubrication to the valve lifters

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

    • The SHLA - valve lifter
    • The oil filter bypass valve
    • The oil pump and pump screen
    • The cylinder head oil galleries
    • The engine block oil galleries

Worn or dirty SHLAs, valve lifters

Replace the SHLAs - valve lifters.

Stretched or broken timing belt and/or damaged sprocket teeth

Replace the timing belt and sprockets.

Worn timing belt tensioner or tensioners

Replace the timing belt tensioner or tensioners as required.

Worn engine camshaft lobes

    • Inspect the engine camshaft lobes.
    • Replace the camshaft or camshafts and SHLAs, 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