GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Remove the valve rocker arm cover. Refer to:
  2. •  Valve Rocker Arm Cover Replacement - Left Side .
    •  Valve Rocker Arm Cover Replacement - Right Side .

    Object Number: 480526  Size: SH

    Important: Mark, sort, and organize all the components for assembly.

  3. Remove the valve rocker arms.

  4. Object Number: 480527  Size: SH
  5. Remove the valve rocker arm supports.

  6. Object Number: 480529  Size: SH
  7. Remove the valve pushrods.

  8. Object Number: 480551  Size: SH

    Important: Parts that are to be reused must be marked, sorted, and organized for assembly.

  9. Mark, sort, and organize the components for assembly.
  10. Caution: Wear safety glasses in order to avoid eye damage.

  11. Clean the components with cleaning solvent.
  12. Dry the components with compressed air.
  13. Inspect the valve rocker arm components for the following:
  14. • Valve rocker arm valve pushrod socket contact surface (1)
    • The contact surface must be smooth with no scoring or excessive wear.
    • Valve rocker arm roller pivot for binding or damage (2)
    • Valve rocker arm valve stem contact surface (3)
    • The contact surface should be smooth with no scoring or excessive wear.
    • Valve rocker arm bolt threads for damage (4)

    Object Number: 488857  Size: SH
  15. Inspect the valve pushrods for the following:
  16. • Restriction of the oil passage (1)
    • Wear or scoring of the end contact surfaces (2)
    • The end contact surfaces must be smooth with no scoring or excessive wear.
    • Shaft for bends (3)
    • Roll the valve pushrod on a flat surface to determine if the valve pushrod is bent.

    Object Number: 480553  Size: SH
  17. Inspect the valve rocker support for excessive wear or damage.

Installation Procedure


    Object Number: 480529  Size: SH

    Important: Be sure to keep parts in order. Parts must be reinstalled into the original location and position.

  1. Install the valve pushrods.

  2. Object Number: 480578  Size: SH

    Important: Be sure that the arrow on the valve rocker arm support is in the up position.

  3. Install the valve rocker arm supports.

  4. Object Number: 480551  Size: SH
  5. Apply prelube GM P/N 12345501 or equivalent to the following valve rocker arm contact surfaces:
  6. • Valve pushrod socket (1)
    • Roller pivot (2)
    • Valve stem tip (3)

    Object Number: 480580  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.

  7. Install the valve rocker arm assemblies as follows:
  8. 4.1. Finger start the bolt at location (1)
    4.2. Finger start the bolt at location (2)
    4.3. Finger start the bolt at location (3)
    4.4. Finger start the remaining valve rocker arm bolts

    Object Number: 334551  Size: SH
  9. Rotate the crankshaft balancer to position the crankshaft balancer alignment mark (1) 57-63 degrees clockwise or counterclockwise from the engine front cover alignment tab (2).
  10. Important: Once the valve rocker arm assemblies are installed and properly torqued, no additional valve lash adjustment is required.

  11. Tighten the valve rocker arm bolts.
  12. Tighten
    Tighten valve rocker arm bolts to 30 N·m (22 lb ft).

  13. Install the valve rocker arm cover. Refer to:
  14. •  Valve Rocker Arm Cover Replacement - Left Side .
    •  Valve Rocker Arm Cover Replacement - Right Side .