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.

Loose and/or worn valve rocker arm attachments |

• | Inspect the valve rocker arm stud, nut or bolt.

• | Repair or replace as required.

Worn or damaged valve rocker arm | Repair or replace as required.
Improper lubrication to the valve rocker arms | Inspect the following components, and repair or replace as required:

• | The valve rocker arm

• | The valve lifter

• | The oil filter bypass valve

• | The oil pump and pump screen

• | The engine block oil galleries

Broken valve spring | Replace the valve spring.
Excessive valve lash |

• | Inspect valve lash adjusters.

• | Replace as required.

Bent valve pushrod |

• | Inspect valve pushrod and valve rocker arm.

• | Repair or replace as required.

Worn or dirty valve lash adjusters | Replace the valve lash adjusters.
Stretched or broken timing chain and/or damaged sprocket teeth | Replace the timing chain and sprockets.
Worn, damaged, or faulty timing chain tensioners | Replace tensioners
Worn engine camshaft lobes |

• | Inspect the engine camshaft lobes.

• | Replace the camshaft and valve lash adjusters 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

Damaged or misaligned timing gears |

• | Inspect timing gears.

• | Replace all damaged components.