For 1990-2009 cars

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 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