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 valve lash adjustment

    • Refer to Valve Clearance Adjustment .
    • 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 rocker arm
    • The oil filter bypass valve
    • The oil control valve
    • The oil pump and pump screen
    • 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

    • Inspect the engine camshaft lobes.
    • Replace the camshaft. Refer to Camshaft Replacement .

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