GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 44212 Camshaft Holding Tool

Removal Procedure

  1. Remove the left secondary camshaft drive chain tensioner. Refer to Secondary Camshaft Drive Chain Tensioner Replacement - Left Side .
  2. Remove the left camshaft cover. Refer to Camshaft Cover Replacement - Left Side .

  3. Object Number: 517149  Size: SH
  4. Ensure both camshaft sprocket drive pins are at the top of their rotation.

  5. Object Number: 650538  Size: SH

    Caution: The camshaft holding tools must be installed on the camshafts to prevent camshaft rotation. When performing service to the valve train and/or timing components, valve spring pressure can cause the camshafts to rotate unexpectedly and can cause personal injury.

  6. Install the J 44212 over the camshafts.
  7. Notice: Refer to Torque Reaction Against Timing Drive Chain Notice in the Preface section.


    Object Number: 749358  Size: SH
  8. Use an open end wrench on the hex cast into the camshaft in order to prevent the camshaft from rotating when removing the camshaft sprocket bolt.

  9. Object Number: 685360  Size: SH
  10. Remove the left exhaust camshaft sprocket bolt.
  11. Slide the left exhaust camshaft sprocket off of the camshaft and remove the left secondary drive chain from the camshaft sprocket teeth.

  12. Object Number: 748194  Size: SH
  13. Remove the left secondary camshaft drive chain guide access plug (4) located in the cylinder head. Ensure the O-ring seal remains attached to the access plug.

  14. Object Number: 685354  Size: SH
  15. Remove the upper left secondary camshaft drive chain guide bolt.

  16. Object Number: 685368  Size: SH
  17. Remove the lower left secondary camshaft drive chain guide bolt.

  18. Object Number: 685372  Size: SH
  19. Remove the left secondary camshaft drive chain guide.
  20. Clean and inspect the camshaft timing drive components. Refer to Camshaft Timing Drive Components Cleaning and Inspection .

Installation Procedure


    Object Number: 685372  Size: SH
  1. Position the left secondary camshaft drive chain guide in through the top of the cylinder head.

  2. Object Number: 685368  Size: SH
  3. Loosely install the lower left secondary camshaft drive chain guide bolt.

  4. Object Number: 685354  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 upper left secondary camshaft drive chain guide bolt.
  6. Tighten
    Tighten the secondary camshaft drive chain guide bolts to 25 N·m (18 lb ft).


    Object Number: 748194  Size: SH
  7. Install the left secondary camshaft drive chain guide access plug (4) located in the cylinder head. Ensure the O-ring seal is attached to the access plug.
  8. Tighten
    Tighten the secondary camshaft drive chain guide access plug to 4.5 N·m (40 lb in).


    Object Number: 517149  Size: SH
  9. Install the left exhaust camshaft sprocket into the left secondary camshaft drive chain.
  10. Install the left exhaust camshaft sprocket onto the camshaft. The camshaft sprocket notch marked LE (left exhaust) engages the exhaust camshaft pin.
  11. Notice: Refer to Torque Reaction Against Timing Drive Chain Notice in the Preface section.


    Object Number: 749358  Size: SH
  12. Use an open end wrench on the hex cast into the camshaft in order to prevent the camshaft from rotating when tightening the camshaft sprocket bolt.

  13. Object Number: 685360  Size: SH
  14. Install the left exhaust camshaft sprocket bolt.
  15. Tighten
    Tighten the camshaft sprocket bolt to 120 N·m (89 lb ft).


    Object Number: 650538  Size: SH
  16. Remove the J 44212 from the camshafts.
  17. Install the left camshaft cover. Refer to Camshaft Cover Replacement - Left Side .
  18. Install the left secondary camshaft drive chain tensioner. Refer to Secondary Camshaft Drive Chain Tensioner Replacement - Left Side .