GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

    Important: When performing any service procedure that pertains to the camshaft or the camshaft actuator, unlock the camshaft actuator locking pin. Refer to Camshaft Actuator Locking Pin Adjustment .

  1. Remove the timing chain from the engine. Refer to Timing Chain and Sprocket Replacement .

  2. Object Number: 625497  Size: SH
  3. Remove the exhaust camshaft sprocket bolt.

  4. Object Number: 625493  Size: SH
  5. Remove the cam sprocket.

  6. Object Number: 427004  Size: SH
  7. Remove the exhaust camshaft bearing cap bolts in sequence. Starting at the ends and working toward the center of the camshaft.
  8. Remove the front camshaft bearing cap (5).
  9. Remove the exhaust camshaft from the cylinder head.
  10. Remove and inspect the lifters for wear, replace as necessary.

Installation Procedure


    Object Number: 235547  Size: SH
  1. Install the exhaust camshaft onto the cylinder head with the number 1 cam lobes facing as shown.
  2. Important: Each bearing cap has a number and a directional arrow marked on the bearing cap.

  3. Install the camshaft bearing caps in their proper locations and direction.

  4. Object Number: 427004  Size: SH

    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 camshaft bearing cap bolts.
  6. Tighten

        • Tighten the camshaft bearing cap bolts in the sequence shown to 13 N·m (10 lb ft).
        • Tighten the front bearing cap bolts to 23 N·m (17 lb ft).

    Object Number: 625493  Size: SH
  7. Install the exhaust camshaft sprocket to the camshaft.

  8. Object Number: 625497  Size: SH
  9. Install the camshaft sprocket bolt in order to secure the cam sprocket.
  10. Tighten
    Tighten the bolt to 55 N·m (40 lb ft).

  11. Install the intake camshaft actuator to the camshaft.
  12. Unlock the camshaft actuator locking pin. Refer to Camshaft Actuator Locking Pin Adjustment .
  13. Install the timing chain onto the engine. Refer to Timing Chain and Sprocket Replacement .
  14. Check and adjust valve clearance. Refer to Valve Lash Adjustment .