GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 309859  Size: SH
  1. Remove the intake manifold. Refer to Intake Manifold Replacement .
  2. Gently pry up the rubber grommets.
  3. Disconnect the knock sensor wire harness electrical connectors.

  4. Object Number: 309864  Size: SH
  5. Remove the knock sensors.

  6. Object Number: 668798  Size: SH
  7. Remove the engine valley cover bolts.
  8. Remove the engine valley cover and gasket.
  9. Discard the engine valley cover gasket.

  10. Object Number: 490851  Size: SH
  11. Remove the knock sensor oil seals (1) from the cover (2).
  12. Clean and inspect the engine valley cover. Refer to Engine Block Valley Cover Cleaning and Inspection .

Installation Procedure

Important: All gasket surfaces should be free of oil or other foreign material during assembly.


    Object Number: 490851  Size: SH
  1. Install NEW knock sensor oil seals (1) into the valley cover (2).
  2. Lubricate the seal surfaces with clean engine oil.


    Object Number: 668798  Size: SH
  3. Install the engine valley cover and a NEW gasket.
  4. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  5. Install the engine valley cover bolts.
  6. Tighten
    Tighten the engine valley cover bolts to 25 N·m (18 lb ft).


    Object Number: 309864  Size: SH
  7. Install the knock sensors.
  8. Tighten
    Tighten the knock sensors to 20 N·m (15 lb ft).


    Object Number: 309859  Size: SH
  9. Connect the knock sensor wire harness electrical connectors.
  10. Install the rubber grommets into the valley cover.
  11. Install the intake manifold. Refer to Intake Manifold Replacement .