GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • EN 46328 Camshaft Holding Tool
    • J 39946 Crankshaft Socket - 4.0L and 4.6L

Removal Procedure

  1. Remove the right camshaft cover. Refer to Camshaft Cover Replacement - Right Side.
  2. Remove the engine oil pump. Refer to Oil Pump Replacement.

  3. Object Number: 517185  Size: SH
  4. Align the primary timing marks (1) using the J 39946 .

  5. Object Number: 1275659  Size: SH
  6. Install the EN 46328  (1) on the right bank camshafts (2).

  7. Object Number: 1275692  Size: SH
  8. Create two reference marks (1) using a paint stick to identify the chain link adjacent to each actuator timing mark (2, 3).

  9. Object Number: 749349  Size: SH
  10. Install an engine front cover bolt (2) into the front of the engine.
  11. Note: Securing the right secondary camshaft drive chain shoe will prevent the right camshaft drive sprocket teeth from skipping on the right secondary timing chain.

  12. Wrap mechanics wire (1) tightly around both the right secondary camshaft drive chain shoe (3) and the front cover bolt (2).

  13. Object Number: 1276761  Size: SH
  14. Remove the 2 bolts attaching the right secondary camshaft drive chain tensioner to the engine block.
  15. Remove the right secondary camshaft drive chain tensioner, allowing the tensioner to expand as you remove it.
  16. Clean and inspect the camshaft timing drive components. Refer to Camshaft Timing Drive Components Cleaning and Inspection.

Installation Procedure


    Object Number: 749346  Size: SH
  1. Collapse the right secondary camshaft chain tensioner using the following procedure:
  2. 1.1. Rotate the ratchet release lever (2) counterclockwise and hold.
    1.2. Collapse the tensioner shoe (1) and hold.
    1.3. Release the ratchet lever (2).
  3. Slowly release the pressure on the shoe (1), until the ratchet lever (2) moves to the first detent and a "click" is heard and felt.
  4. Collapse the tensioner shoe (1) and hold.

  5. Object Number: 749348  Size: SH
  6. Insert a pin through the hole in the release lever in order to lock the tensioner shoe in the collapsed position.
  7. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1276761  Size: SH

    Note: Ensure the tensioner release lever is facing outward.

  8. Install the right secondary camshaft drive chain tensioner and retaining bolts and tighten to 25 N·m (18 lb ft).
  9. Remove the pin holding the tensioner to tighten any slack in the timing chain.

  10. Object Number: 1275693  Size: SH
  11. Inspect the two paint marks (1, 3) created previously to ensure they remain aligned with the timing marks (2, 4) on the actuator.

  12. Object Number: 749349  Size: SH
  13. Remove the mechanics wire (1) supporting the right secondary camshaft drive chain shoe (3).
  14. Remove the engine front cover bolt (2) from the front of the engine.
  15. Install the engine oil pump. Refer to Oil Pump Replacement.

  16. Object Number: 1275659  Size: SH
  17. Remove the EN 46328  (1).
  18. Install the right camshaft cover. Refer to Camshaft Cover Replacement - Right Side.