GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • EN 46116 Valve Stem Seal Remover/Installer
    • EN 46117 Valve Stem Key Remover/Installer
    • EN 46119 Off-Vehicle Valve Spring Compressor Adapter
    • EN-46122 Camshaft Position Actuator Check-Ball Valve Remover/Installer
    • J 8062 Valve Spring Compressor - Head Off
    • J 2619-01 Slide Hammer
    • J-37281-A Injector Remover

For equivalent regional tools, refer to Special Tools.


    Object Number: 1977939  Size: SH
  1. Remove and discard high pressure fuel line. - LH Cylinder Head

  2. Object Number: 1977940  Size: SH
  3. Remove and discard high pressure fuel pump bolts (1). - LH Cylinder Head
  4. Remove the high pressure fuel pump (2). - LH Cylinder Head
  5. Remove and discard the high pressure fuel pump gasket (3). - LH Cylinder Head
  6. Remove and discard the high pressure fuel pump O-ring (4). - LH Cylinder Head

  7. Object Number: 1977944  Size: SH
  8. Remove the fuel rail bolts.
  9. Remove the fuel rail and injectors.

  10. Object Number: 1977946  Size: SH
  11. The injectors may stay in the cylinder head. Remove the fuel injector hold-down clamp before removing the injector.
  12. Use the J-37281-A remover and the J 2619-01 hammer to remove the injector.

  13. Object Number: 1977948  Size: SH
  14. Remove the engine coolant temperature (ECT) sensor. - LH Cylinder Head

  15. Object Number: 2004262  Size: SH
  16. Remove the spark plugs.

  17. Object Number: 1977949  Size: SH

    Note: Ensure valve heads will not contact anything during the following step in order to avoid bending or damage.

  18. Using an appropriately sized deep socket and a plastic hammer, lightly tap on the valve spring retainer to loosen the valve keepers.

  19. Object Number: 1977952  Size: SH

    Warning: Natural gas is stored under high pressure. If a leak occurs, the high pressure could cause a personal injury. In order to prevent Compressed Natural Gas (CNG) fuel leaks, always replace the CNG fuel system O-rings during service.

    Caution: Do not compress the valve springs less than 24.0 mm (0.943 in). Contact between the valve spring retainer and the valve stem oil seal can cause potential valve stem oil seal damage.

  20. Compress the valve spring using the J 8062 compressor and the EN 46119 adapter .

  21. Object Number: 1977955  Size: SH
  22. Use the magnet of the EN 46117 remover/installer in order to remove the valve keepers.
  23. Remove the valve spring compressor and the adapter.

  24. Object Number: 1977958  Size: SH
  25. Remove the valve spring retainer.
  26. Remove the valve spring.

  27. Object Number: 1977960  Size: SH
  28. Remove the valve.

  29. Object Number: 1977962  Size: SH

    Note: NEVER reuse a valve stem oil seal.

  30. Remove the valve stem oil seal using the EN 46116 remover/installer and discard.
  31. Repeat these procedures for the remaining valves.

  32. Object Number: 1977963  Size: SH
  33. Remove the cylinder head oil gallery expansion plugs.

  34. Object Number: 1977967  Size: SH
  35. Remove the cylinder head coolant threaded plugs.

  36. Object Number: 1492615  Size: SH
  37. Inspect the camshaft position actuator oil feed check valves. Damaged, restricted or clogged check valves must be replaced.

  38. Object Number: 2164009  Size: SH
  39. Place cylinder head on firm surface with check valves (1) facing up. Protect all cylinder head components and machined surfaces.
  40. Using drill bit EN-46122-3, drill out top portion of check valve to expose internal check ball.

  41. Object Number: 2164015  Size: SH
  42. Remove check ball (1) and check ball spring (2) from inside of check valve.

  43. Object Number: 2164020  Size: SH
  44. Continue drilling remainder of check valve sleeve to a depth of approximately 19 mm (0.75 in) (a) by placing tape on drill bit as a depth gauge. It is not necessary or desirable to drill completely through the bottom of the check valve.

  45. Object Number: 2164025  Size: SH
  46. Lubricate tap EN-46122-4 with lubricant included in EN-46122 remover/installer . Tap drilled out portion of check valve (1) remaining in cylinder head. Tap to full depth possible until tap bottoms out in head.

  47. Object Number: 2164028  Size: SH
  48. Assemble bolt, nut, washers, and collar EN-46122-2 (1) as shown. Position collar with slightly-larger inside diameter DOWN toward the cylinder head.
  49. Screw bolt by hand fully down into threaded check valve sleeve, then lightly tighten nut against washer.

  50. Object Number: 2164030  Size: SH
  51. Hold bolt with one wrench, and use another to tighten the nut until the check valve sleeve (1) is removed from the cylinder head.
  52. Clean check valve bore and related passages thoroughly to remove any drilling chips or other debris.