GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Important: This engine uses a sequential multiport fuel injection system. Injector wiring harness connectors must be connected to their appropriate fuel injector or exhaust emissions and engine performance may be seriously affected.

  1. Remove the coolant crossover pipe. Refer to Engine Coolant Crossover Pipe Replacement .
  2. Remove the upper intake manifold. Refer to Upper Intake Manifold Replacement .
  3. Remove the left valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement - Left Side .
  4. Remove the right valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement - Right Side .
  5. Disconnect the engine coolant temperature (ECT) electrical connector.
  6. Disconnect the fuel feed line from the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .

  7. Object Number: 1582090  Size: SH
  8. Disconnect the fuel injector inline connector (2).

  9. Object Number: 1557674  Size: SH
  10. Remove the fuel injector harness connector bracket bolt from the intake manifold.
  11. Disconnect the camshaft position (CMP) sensor electrical connector.
  12. Remove the fuel injector rail bolts.
  13. Remove the fuel rail (1).

  14. Object Number: 54281  Size: SH
  15. Remove the lower intake manifold bolts.
  16. Remove the lower intake manifold.

  17. Object Number: 1557679  Size: SH
  18. Loosen the valve rocker arm bolts.
  19. Important: Place the valve train components in a rack in order to ensure that the components are installed in the same location from which they where removed.

  20. Remove the valve rocker arms.
  21. Remove the push rods.
  22. • The intake push rods measure 147.51 mm (5.81 in).
    • The exhaust push rods measure 154.87 mm (6.1 in).

    Object Number: 1557681  Size: SH
  23. Remove the lower intake manifold gaskets and seals.
  24. Clean the lower intake manifold gasket and seal surfaces on the cylinder heads and the engine block.
  25. Clean the gasket and seal surfaces on the lower intake manifold with degreaser.
  26. Remove all the loose room temperature vulcanizing sealer (RTV).

Installation Procedure

Important: All gasket mating surfaces need to be free of oil and foreign material. Use lubricant to clean the surfaces. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.


    Object Number: 1557681  Size: SH

    Important: RTV sealer is NOT to be placed under the lower intake manifold gaskets.

  1. Install the lower intake manifold gaskets and seals.

  2. Object Number: 1557679  Size: SH
  3. Coat the ends of the push rods using prelube. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  4. Important: The intake valve push rods measure 146.0 mm (5.75 in) and the exhaust valve push rods measure 152.5 mm (6.0 in).

  5. Install the push rods in their original location.
  6. Coat the rocker arm friction surfaces using prelube. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  7. Notice: Refer to Fastener Notice in the Preface section.

    Important: Shims (P/N 88894006) may be required under the valve rocker arm pedestals if reconditioning has been performed on the cylinder head or its components.

  8. Install the valve rocker arms in their original positions.
  9. Install the valve rocker arm bolts.
  10. Tighten
    Tighten the bolts to 34 N·m (25 lb ft).


    Object Number: 1313742  Size: SH
  11. With the NEW gaskets and seals in place, apply a small drop, 8-10 mm (0.031-0.39 in) of RTV sealer to the 4 corners of the intake manifold to engine block joints (1). Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  12. Install the lower intake manifold.

  13. Object Number: 1557861  Size: SH

    Notice: Maximum gasket performance is achieved when using new fasteners, which contain a thread-locking patch. If the fasteners are not replaced, a thread locking chemical must be applied to the fastener threads. Failure to replace the fasteners or apply a thread-locking chemical MAY reduce gasket sealing capability.

    Notice: Failure to tighten vertical bolts before the diagonal bolts may cause an oil leak.

  14. Apply sealer to the lower intake manifold bolt threads. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  15. Install the lower intake manifold bolts.
  16. Tighten the lower intake manifold bolts in the sequence shown.
  17. Tighten

    1. Tighten the bolts (1, 2, 3, 4) in sequence to 16 N·m (12 lb ft).
    2. Tighten the bolts (5, 6, 7, 8) in sequence to 25 N·m (18 lb ft).

    Object Number: 1557674  Size: SH
  18. Inspect the fuel rail, fuel injectors and fuel injector O-rings for damage and replace as necessary.
  19. Lubricate the fuel injector O-rings using lubricant. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  20. Install the injector nozzles into the lower intake manifold injector bores.
  21. Press on the injector rail (1) using the palms of both hands until the injector is fully seated.
  22. Install the fuel injector rail bolts.
  23. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  24. Connect the CMP sensor electrical connector.
  25. Position the fuel injector harness connector bracket to the intake manifold.
  26. Install the fuel injector harness connector bracket bolt.
  27. Tighten
    Tighten the bolt to 8 N·m (71 lb in).


    Object Number: 1582090  Size: SH
  28. Connect the fuel injector inline connector (2).
  29. Connect the fuel feed line to the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .
  30. Connect the ECT electrical connector.
  31. Install the right valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement - Right Side .
  32. Install the left valve rocker arm cover. Refer to Valve Rocker Arm Cover Replacement - Left Side .
  33. Install the upper intake manifold. Refer to Upper Intake Manifold Replacement .
  34. Install the coolant crossover pipe. Refer to Engine Coolant Crossover Pipe Replacement .