GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Low oil pressure

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

Improper valve lash adjustment

    â€¢ Refer to Valve Clearance Adjustment .
    â€¢ Repair or replace as required.

Improper lubrication to the valve train

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

    â€¢ Restricted oil filter
    â€¢ The rocker arm
    â€¢ The oil filter bypass valve
    â€¢ The oil control valve
    â€¢ The oil pump and pump screen
    â€¢ The engine block oil galleries

Broken valve spring

Replace the valve spring.

Stretched or broken timing belt and/or damaged sprocket teeth

Replace the timing belt and sprockets. Refer to Timing Belt Replacement .

Worn engine camshaft lobes

    â€¢ Inspect the engine camshaft lobes.
    â€¢ Replace the camshaft. Refer to Camshaft Replacement .

Worn valve guides or valve stems

Inspect the following components, and repair as required:

    â€¢ The valves
    â€¢ 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:

    â€¢ The valves
    â€¢ The valve guides