GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Raise the vehicle. Support the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Open the hood.
  3. Remove the right engine splash guard.
  4. Lower the vehicle.
  5. Remove the timing belt upper front cover. Refer to Timing Belt Upper Front Cover Removal.
  6. Remove the spark plugs. Refer to Spark Plug Replacement.
  7. Detach the engine management wiring harness from intake manifold, cylinder head cover.
  8. Remove from bracket.

  9. Remove the coolant expansion tank closure cap.
  10. Remove the oil dipstick.

  11. Object Number: 1936993  Size: SH
  12. Set up the crankshaft.
  13. Move the crankshaft in the direction of the engine rotation to the first cylinder TDC position (mark 1).


    Object Number: 1945804  Size: SH
  14. Apply guidance marks.
  15. Attach 3 markings (2) as an aid to one of the camshaft adjusters, each one offset by 90 degrees to the marking applied (1).

Test Procedure

    Note: Follow manufacturer instructions.

  1. Calibrate the pressure loss tester.
  2. Connect to the compressed air system.


    Object Number: 1937002  Size: SH
  3. Install the pressure loss tester.
  4.    Note: Wheels must be in contact with the ground.

    • Engage first gear and apply the parking brake.
    • Install the connecting piece into the spark plug thread of cylinder number 1.
    • Apply compressed air to cylinder number 1.
  5. Pressure Loss, Check
  6. • Take pressure loss reading.
       - The maximum permissible pressure differential between cylinders is approximately 10 percent.
       - Maximum pressure loss of a cylinder is 25 percent.
    • Take note of any visible escape of compressed air.
      Intake manifold, exhaust manifold, crankcase
    • Take note of any bubble formation in the coolant compensation tank.
  7. Perform pressure loss test by analogy on cylinders 3, 4 and 2.

Installation Procedure

  1. Remove the pressure loss tester.
  2. Remove the connection piece from the spark plug thread.

  3. Put the vehicle in neutral.
  4. Insert the oil dipstick.
  5. Install the coolant expansion tank closure cap.
  6. Install the spark plugs. Refer to Spark Plug Replacement.
  7. Install the engine management wiring harness to the intake manifold.
  8. Install the timing belt upper front cover. Refer to Timing Belt Upper Front Cover Installation.
  9. Raise the vehicle by its full height.
  10. Install the right engine splash guard.
  11. Lower the vehicle.
  12. Close the hood.