GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J 38820 Valve Stem Seal Remover and Installer
    • J 44222 Camshaft Sprocket Holding Tool
    • J-44228-A Valve Spring Compressor
    • J 44226 Crankshaft Balancer Remover

Removal Procedure

    Note: 

       • Organize the valve train components when disassembling so they can be reassembled in the same location and matched up with the same components, as previously installed.
       • Regulate the air pressure to 50 psi before pressurizing the cylinder to help prevent the crankshaft from turning.

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.

  2. Object Number: 744183  Size: SH
  3. Remove the torque converter access plug.
  4. Use the J 44226-3A 15 mm holding bar on a torque converter bolt to prevent the crankshaft from turning.
  5. Lower the vehicle.

  6. Object Number: 760724  Size: SH
  7. Remove and discard the timing gear bolts.
  8. Install the J 44222 onto the cylinder head in order to keep from disturbing the timing chain components.
  9. Adjust the 2 horizontal bolts into the camshaft sprockets to maintain chain tension.
  10. Carefully move the sprockets with the timing chain, off of the camshafts.
  11. Remove the camshaft cap bolts.

  12. Object Number: 637767  Size: SH

    Note: Place the camshaft caps in a rack to ensure the caps are installed in the same location from which they were removed.

  13. Remove the camshaft caps.

  14. Object Number: 637768  Size: SH
  15. Remove the camshafts.
  16. Using a suitable adapter, apply air pressure to the cylinder.

  17. Object Number: 760725  Size: SH
  18. Install the J-44228-A and compress the valve springs.

  19. Object Number: 659577  Size: SH
  20. Remove the valve keys.
  21. Remove the J-44228-A .

  22. Object Number: 637700  Size: SH
  23. Remove the valve spring retainer and the valve spring.

  24. Object Number: 637703  Size: SH
  25. Use the J 38820 and remove the seals.
  26. Clean and inspect the cylinder head. Refer to Cylinder Head Cleaning and Inspection.

Installation Procedure

    Note: Lubricate the valve stems with clean engine oil before installing.


    Object Number: 637703  Size: SH
  1. Use the J 38820 to install the valve seals. There is only one size seal.

  2. Object Number: 637700  Size: SH
  3. Install the valve spring and the valve spring retainer.

  4. Object Number: 760725  Size: SH
  5. Use the J-44228-A and compress the valve springs.

  6. Object Number: 659577  Size: SH
  7. Install the valve keys.
  8. Remove the J-44228-A .
  9. Remove the air pressure to the cylinder.
  10. Coat the camshaft journals, the camshaft journal thrust face, and the camshaft lobes with clean engine oil.

  11. Object Number: 637768  Size: SH
  12. Install the camshafts to their original position.
  13. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 637767  Size: SH
  14. Install the camshaft caps onto their original journal. Tighten the camshaft cap bolts to 12 N·m (106 lb in).

  15. Object Number: 760724  Size: SH
  16. Carefully move the camshaft sprockets back onto the camshafts and remove the J 44222 .
  17. Install a NEW intake camshaft sprocket washer and bolt, and a NEW exhaust camshaft actuator bolt.
  18. • Tighten the intake camshaft sprocket bolt the first pass to 20 N·m (15 lb ft).
    • Use the J 36660-A to tighten the intake camshaft sprocket bolt the final pass and additional 100 degrees.
    • Tighten the exhaust camshaft actuator bolt the first pass to 25 N·m (18 lb ft).
    • Use the J 36660-A to tighten the exhaust camshaft actuator bolt a final pass an additional 135 degrees.
  19. Install the spark plugs. Refer to Spark Plug Replacement.
  20. Install the camshaft cover. Refer to Camshaft Cover Replacement.
  21. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  22. Remove the J 44226-3A from the torque converter bolt.

  23. Object Number: 744183  Size: SH
  24. Install the torque converter access plug.
  25. Lower the vehicle.