Important: 
|    •  | Do not use the valley cover knock sensor oil seals again. Install NEW oil seals during assembly. | 
 
|    •  | Do not use the valley cover gasket again. Install a NEW gasket during assembly. | 
 
- Remove the knock sensor oil seals (520) from the valley cover (555).
 
- Clean the valley cover in solvent.
 
Caution: Refer to Safety Glasses Caution in the Preface section.
- Dry the valley cover with compressed air.
 
- Inspect the gasket sealing surfaces for excessive scratches or gouging. Refer to 
Replacing Engine Gaskets
 .
 
- Inspect the valley cover oil seal bores for excessive scratches or gouging.