Low oil pressure

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

Loose and/or worn valve rocker arm attachments

1. Inspect the valve rocker arm stud, nut, or bolt.
2. Repair or replace as required.

Worn valve rocker arm

Replace the valve rocker arm.

Improper lubrication to the valve rocker arms

Inspect the following components and repair or replace as required:

1. The valve rocker arm
2. The tappet
3. The oil filter bypass valve
4. The oil pump and pump screen
5. The engine block oil galleries

Broken valve spring

Replace the valve spring.

Worn or dirty tappets

Replace the tappets.

Stretched or broken timing belt and/or damaged sprocket teeth

Replace the timing belt and sprockets.

Worn, damaged, or faulty timing belt tensioners

Replace tensioners

Worn engine camshaft lobes

1. Inspect the engine camshaft lobes.
2. Replace the camshaft and tappets as required.

Worn valve guides or valve stems

Inspect the following components, and repair as required:

1. The valves
2. The valve guides

Inspect the following components and repair as required:

1. The valves
2. The valve guides