Important: The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.

Engine oil level overfull, causing aeration

Drain excess oil and adjust oil level to proper specification.

Low oil pressure

1. Perform an oil pressure test. Refer 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.

Bent or damaged push rod

Inspect the following components, and replace as required:

Improper lubrication to the valve rocker arms

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

Broken valve spring

Replace the valve spring.

Worn and/or damaged valve rotators

Replace the valve rotators 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 timing chain tensioner, if applicable

Replace the timing chain tensioners as required.

Worn engine camshaft lobes

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

Damaged, broken, or dirty, balance shaft sprocket teeth, if applicable

Inspect the following components, and repair as required:

Worn valve guides or valve stems

Inspect the following components, and repair as required:

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:

Malfunctioning camshaft position actuator--Improper viscosity oil, contaminated oil, or a plugged or missing camshaft position actuator filter can cause the camshaft position actuator locking pin to malfunction.

1. Verify correct oil viscosity by changing the engine oil and oil filter and re-evaluating the concern.
2. Inspect for a missing or plugged camshaft position actuator filter.
3. If filter is missing, replace the filter, replace the camshaft position actuator, and change the engine oil and oil filter.
4. If filter is plugged, replace the filter, and change the engine oil and oil filter.
5. If no problem is found with the camshaft position actuator filter, replace the camshaft position actuator and change the engine oil and oil filter.