Cause
| Correction
|
Low oil pressure.
| Perform an oil pressure test. Refer to
Oil Pressure Diagnosis and Testing.
|
Loose and/or worn valve rocker arm attachments.
|
- Inspect the valve rocker arm, bolt, and pedestal.
- Replace the valve rocker arms, as required. Refer to
Valve Rocker Arm and Push Rod Replacement.
|
Worn or damaged valve rocker arm.
|
- Inspect the rocker arm for wear or missing needle bearings
- Replace the valve rocker arms, as required. Refer to
Valve Rocker Arm and Push Rod Replacement.
|
Bent or damaged push rod.
| Inspect the following components and replace, as required:
| • | The valve lifter guide. |
| • | Inspect the top of the pistons for valve contact. If the top of the piston
shows valve contact, replace the piston and pin assembly. |
|
Incorrect lubrication to the valve rocker arms.
| Inspect the following components and repair or replace, as required:
| • | The oil filter bypass valve. |
| • | The oil pump and pump screen. |
| • | The engine block oil galleries. |
|
Broken valve spring.
| Replace the valve spring and spring shim. Refer to
Valve Stem Oil Seal and Valve Spring Replacement.
|
Worn or dirty valve lifters.
| Replace the valve lifters. Refer to
Valve Lifter Replacement.
|
Stretched or broken timing chain and/or damaged sprocket teeth.
| Replace the timing chain and sprockets. Refer to
Camshaft Timing Chain and Sprocket Replacement.
|
Worn engine camshaft lobes.
|
- Inspect the engine camshaft lobes.
- Replace the camshaft and valve lifters, as required. Refer to
Camshaft Replacement.
|
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:
|
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, bolt, and pedestal.
- Repair or replace, as required.
|
Worn or damaged valve rocker arm
|
- Inspect the rocker arm for wear or missing needle bearings
- Replace the valve rocker arms, as required.
|
Bent or damaged push rod
| Inspect the following components and replace, as required:
Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.
|
Improper lubrication to the valve rocker arms
| Inspect the following components and repair or replace, as required:
| • | The oil filter bypass valve |
| | The bypass valve is now internal to the oil filter. |
| • | The oil pump and pump screen |
| • | The engine block oil galleries |
|
Broken valve spring
| Replace the valve spring and spring shim.
|
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:
|
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:
|
