GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • EN-46105 Camshaft Locking Tool
    • EN-46108 Timing Chain Retention Tool
    • EN-46111 Crankshaft Rotation Socket

Removal Procedure


    Object Number: 1796478  Size: SH

    Important: Setting the camshaft timing is required whenever the camshaft drive system is disturbed to ensure the relationship between any chain and sprocket is not lost. Even when only one sprocket is involved, multiple crankshaft rotations will not produce conditions where correct timing can be confirmed. If required, refer to Setting Camshaft Timing installation procedure to reset the camshaft timing.

  1. Remove the engine assembly. Refer to Engine Replacement.
  2. Remove the bank 1 cylinder head cover. Refer to Camshaft Cover Replacement - Right Side.
  3. Remove the camshaft position sensor. Refer to Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust and Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake.
  4. Remove the camshaft position actuator solenoids. Refer to Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Intake and Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Exhaust.
  5. Remove the crankshaft pulley. Refer to Crankshaft Balancer Replacement
  6. Install EN 46111 onto the crankshaft.
  7. Rotate the crankshaft until the camshafts are in a neutral low tension position. The camshaft flats (1) will be parallel with the cylinder head cover rail (2).

  8. Object Number: 1797459  Size: SH
  9. Install EN 46105  (1) onto the bank of the bank 1 cylinder head (3) camshafts (2).

  10. Object Number: 1797462  Size: SH

    Important: Use an open-end spanner (1) at the camshaft hex (2) to prevent camshaft/engine rotation. Disassemble the pump only to diagnose oil related concern. A disassembled oil pump must not be reused, it must be replaced. Do not remove the camshaft position actuator bolt at this time.

  11. Loosen the camshaft position actuator bolt.

  12. Object Number: 1797463  Size: SH

    Important: If you have already removed the camshaft timing chain, proceed to Step 13.

    Important: Ensure the tips of EN 46108 are fully engaged into the timing chain and the wing nuts are tight and the timing chain is taught.

  13. Install EN 46108  (1 and 2) to retain the timing chain (3 and 4).
  14. Firmly tighten the wing nuts of EN 46108 .
  15. Important: Ensure the camshaft timing chain and the camshaft position actuators are marked for correct reassembly.

  16. Mark the timing chain and the respective location on both camshaft position actuators.

  17. Object Number: 1797466  Size: SH
  18. Remove the bolt (1) attaching the bank 1 intake camshaft position actuator (2) and remove the actuator.

Cleaning Procedure

  1. Clean the exterior of each camshaft position actuator with solvent.
  2. Dry the timing components with compressed air.

Inspection Procedure


    Object Number: 1797477  Size: SH
  1. Inspect the front of each camshaft position actuator for the following:
  2. • Sprocket damage (1)
    • Reluctor/sensor wheel damage (2)
    • Camshaft position actuator bolt seating/sealing inner hub flange damage (3)
  3. Inspect the back of each camshaft position actuator for the following:
  4. • Sprocket damage (1)
    • Camshaft locating pin damage (2)
    • Camshaft seating/sealing inner hub flange damage (3)
    • Blockage to the oil passages (4)
    • Loose or missing housing bolts (5)

Installation Procedure


    Object Number: 1797464  Size: SH
  1. Installation should follow the removal procedure in the reverse order.
  2. Align the actuators and timing chain with the marks made during removal.
  3. Caution: Refer to Fastener Caution in the Preface section.

  4. Install the camshaft position actuators and tighten attaching bolts to 58 N·m (43 lb ft).
  5. Remove the timing chain retention tools.