GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Remove the primary camshaft drive chain tensioner. Refer to Primary Camshaft Drive Chain Tensioner Replacement .

  2. Object Number: 742052  Size: SH
  3. Transfer the chain slack from the primary camshaft drive chain tensioner area to the primary camshaft drive chain upper guide area by moving the chain links clockwise around the right intake sprocket.

  4. Object Number: 742050  Size: SH

    Important: Ensure the relationship between the primary camshaft drive chain and balance shaft sprocket remain in a timed sequence.

  5. Rotate the balance shaft counterclockwise in order to transfer the chain slack from the right upper guide to the left upper guide.

  6. Object Number: 742044  Size: SH
  7. Remove the chain guide access plug (3) located in the cylinder head. Note the O-ring seal on the access plug.

  8. Object Number: 742055  Size: SH
  9. Remove the primary drive chain left upper guide bolts.
  10. Remove the primary camshaft drive chain left upper guide by pulling the guide downward through the front cover area.

Installation Procedure


    Object Number: 742055  Size: SH
  1. Install the primary camshaft drive chain left upper guide upward through the front cover area, aligning the guide to the threaded holes in the cylinder head and block.
  2. 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.

  3. Install the primary drive chain left upper guide bolts.
  4. Tighten
    Tighten the primary camshaft drive chain guide bolts to 30 N·m (22 lb ft).


    Object Number: 742044  Size: SH

    Important: Ensure that the chain guide access plug has an O-ring installed.

  5. Install the chain guide access plug (3).
  6. Tighten
    Tighten the chain guide access plug to 5 N·m (44 lb in).


    Object Number: 742050  Size: SH

    Important: Ensure the relationship between the primary camshaft drive chain and balance shaft sprocket remain in a timed sequence.

  7. Rotate the balance shaft clockwise in order to transfer the chain slack from the left upper guide to the right upper guide.

  8. Object Number: 742052  Size: SH
  9. Transfer the chain slack from the primary camshaft drive chain upper guide area to the primary camshaft drive chain tensioner area by moving the chain links counterclockwise around the right intake sprocket.
  10. Install the primary camshaft drive chain tensioner. Refer to Primary Camshaft Drive Chain Tensioner Replacement .