GM Service Manual Online
For 1990-2009 cars only

    Object Number: 490851  Size: SH

    Important: Do not reuse the valley cover knock sensor oil seals. Install NEW oil seals during assembly.

    Do not reuse the valley cover gasket. Install a NEW gasket during assembly.

  1. Remove the knock sensor oil seals (1) from the valley cover (2).
  2. Clean the valley cover in solvent.
  3. Caution: Wear safety glasses in order to avoid eye damage.

  4. Dry the valley cover with compressed air.
  5. Inspect the gasket sealing surfaces for excessive scratches or gouging. Refer to Replacing Engine Gaskets .
  6. Inspect the valley cover oil seal bores for excessive scratches or gouging.