GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 39946 Crankshaft Socket
    • EN 46328 Camshaft Holding Tool

Removal Procedure


    Object Number: 1276759  Size: SH
  1. Remove the left secondary camshaft tensioner. Refer to Secondary Camshaft Drive Chain Tensioner Replacement - Left Side .
  2. Remove the left camshaft position actuator housing. DO NOT remove the camshaft actuator solenoids from the housing. Refer to Camshaft Position Actuator Housing Replacement - Left Side .

  3. Object Number: 1276768  Size: SH
  4. Using the J 39946 , rotate the crankshaft until both camshaft position actuator timing marks (5, 7) are at the top of their rotation.
  5. Caution: Refer to Camshaft Holding Tool Caution in the Preface section.


    Object Number: 1275659  Size: SH
  6. Install the EN 46328  (1) to the camshafts (2).

  7. Object Number: 1275729  Size: SH

    Important: The secondary timing chain has black links that are used for alignment when the primary and secondary timing gear and chain assemblies are being installed together. IT IS NOT NECESSARY for the black chain links to be aligned with the camshaft actuator timing marks when the secondary chain and gear components are being serviced separately.

  8. Use a paint stick to create a mark (1) on the timing chain link adjacent to each camshaft position actuator timing mark (2).
  9. Use a paint stick to create a mark on a primary chain link and intermediate primary chain sprocket tooth adjacent to the primary chain link.
  10. Notice: Refer to Torque Reaction Against Timing Drive Chain Notice in the Preface section.


    Object Number: 1275675  Size: SH
  11. Use an open end wrench on the hex cast into the left intake camshaft to prevent the camshaft from rotating when loosening the camshaft oil control valve.

  12. Object Number: 1261666  Size: SH
  13. Loosen and remove the left intake oil control valve.
  14. Slide the left intake camshaft actuator off of the camshaft, disengage the sprocket teeth from the secondary timing chain, and remove the actuator.

  15. Object Number: 1276762  Size: SH
  16. Remove the left secondary camshaft drive timing chain shoe bolt.
  17. Remove the left secondary camshaft drive timing shoe.
  18. Clean and inspect the camshaft timing drive components. Refer to Camshaft Timing Drive Components Cleaning and Inspection .

Installation Procedure


    Object Number: 1276762  Size: SH
  1. Position the left secondary camshaft drive chain shoe in through the left front cylinder head as shown.
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the left secondary camshaft drive chain shoe bolt.
  4. Tighten
    Tighten the secondary camshaft drive chain shoe bolt to 25 N·m (18 lb ft).


    Object Number: 1275675  Size: SH
  5. Install the left intake actuator to the secondary chain, ensuring that the actuator timing mark is aligned with the chain link that was marked during disassembly.
  6. Loosely install the oil control valve to secure the intake actuator to the camshaft.
  7. Notice: Refer to Torque Reaction Against Timing Drive Chain Notice in the Preface section.

  8. Use an open-end wrench on the hex cast into the camshaft in order to prevent the camshaft from rotating when tightening the oil control valve.
  9. Tighten
    Tighten the oil control valve to 120 N·m (89 lb ft).


    Object Number: 1276759  Size: SH
  10. Install the left secondary camshaft drive chain tensioner. Refer to Secondary Camshaft Drive Chain Guide Replacement - Left Side .

  11. Object Number: 1275693  Size: SH
  12. Ensure that the previously created paint marks (1, 3) still line up with the sprocket timing marks (2, 4).
  13. Install the left camshaft actuator housing. Refer to Camshaft Position Actuator Housing Replacement - Left Side .