GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure


    Object Number: 1686314  Size: SH
  1. Remove the upper intake manifold. Refer to Upper Intake Manifold Replacement .
  2. Remove the drive belt tensioner. Refer to Drive Belt Tensioner Replacement .
  3. Remove the exhaust gas recirculation (EGR) valve outlet pipe bolt and nut.
  4. Remove the EGR valve outlet pipe.

  5. Object Number: 1686393  Size: SH
  6. Using the J 38185 reposition the hose clamp at the thermostat housing.
  7. Remove the radiator inlet hose from the thermostat housing.

  8. Object Number: 1686397  Size: SH
  9. Remove the generator brace bracket bolts.
  10. Remove the generator brace bracket and spacer.

  11. Object Number: 1686400  Size: SH
  12. Remove the lower intake manifold bolts.
  13. Remove the lower intake manifold.

  14. Object Number: 153573  Size: SH
  15. Remove the lower intake manifold seals.

  16. Object Number: 153574  Size: SH
  17. Remove the lower intake manifold gaskets.

  18. Object Number: 1686422  Size: SH
  19. If replacing the lower intake manifold perform the following steps, otherwise proceed to step 5 in the installation procedure.
  20. Remove the engine coolant temperature (ECT) sensor.

  21. Object Number: 1686423  Size: SH
  22. Remove the thermostat housing bolt and stud.
  23. Remove the thermostat housing and thermostat.

Installation Procedure


    Object Number: 1686423  Size: SH
  1. If replacing the lower intake manifold perform the following steps, otherwise proceed to step 5.
  2. Install the thermostat and housing.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the thermostat housing bolt and stud.
  5. Tighten
    Tighten the bolt/stud to 25 N·m (18 lb ft).


    Object Number: 1686422  Size: SH
  6. Install the ECT sensor.
  7. Tighten
    Tighten the sensor to 23 N·m (17 lb ft).


    Object Number: 153574  Size: SH
  8. Clean the lower intake manifold sealing surface prior to installing the seals or gaskets. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  9. Install the lower intake manifold gaskets.

  10. Object Number: 153573  Size: SH
  11. Apply sealer to the ends of the intake manifold seals. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  12. Install the lower intake manifold seals.

  13. Object Number: 1686400  Size: SH
  14. Install the lower intake manifold.
  15. Apply threadlock to the lower intake manifold bolt threads. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  16. Install the lower intake manifold bolts.
  17. Tighten
    Tighten the bolts to 15 N·m (11 lb ft).


    Object Number: 1686397  Size: SH
  18. Install the generator brace bracket and spacer.
  19. Install the generator brace bracket bolts.
  20. Tighten
    Tighten the bolts to 50 N·m (37 lb ft).


    Object Number: 405984  Size: SH
  21. Install the radiator inlet hose to the thermostat housing.
  22. Using the J 38185 position the hose clamp at the thermostat housing.

  23. Object Number: 1686314  Size: SH
  24. Install the EGR valve outlet pipe.
  25. Install the EGR valve outlet pipe bolt and nut.
  26. Tighten
    Tighten the bolt/nut to 25 N·m (18 lb ft).

  27. Install the drive belt tensioner. Refer to Drive Belt Tensioner Replacement .
  28. Install the upper intake manifold. Refer to Upper Intake Manifold Replacement .