GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Replacement LX9

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure


    Object Number: 70064  Size: SH
  1. Remove the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement for the 3.5L (LX9) engine.
  2. Partially drain the cooling system. Refer to Cooling System Draining and Filling .
  3. Use the J 38185 in order to reposition the hose clamp from the thermostat housing.
  4. Remove the radiator inlet hose from the thermostat housing.
  5. Remove the thermostat housing bolts.

  6. Object Number: 30962  Size: SH
  7. Remove the thermostat housing .

  8. Object Number: 30995  Size: SH
  9. Remove the thermostat.
  10. Clean and inspect the thermostat housing gasket mating surfaces.

Installation Procedure


    Object Number: 30995  Size: SH
  1. Install the thermostat.

  2. Object Number: 30962  Size: SH
  3. Install the thermostat housing.
  4. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 70064  Size: SH
  5. Install the thermostat housing bolts.
  6. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

  7. Install the radiator inlet hose to the thermostat housing.
  8. Use the J 38185 in order to reposition and install the hose clamp to the thermostat housing.
  9. Install the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement for the 3.5L (LX9) engine.
  10. Fill the cooling system. Refer to Cooling System Draining and Filling .

Engine Coolant Thermostat Replacement LE5

Removal Procedure


    Object Number: 1713058  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling .
  2. If the vehicle is not equipped an engine oil cooler proceed with the following steps, otherwise proceed to step 7.
  3. Reposition the radiator outlet hose clamp at the surge tank.
  4. Remove the radiator outlet hose from the surge tank.

  5. Object Number: 1712757  Size: SH
  6. Reposition the radiator outlet hose clamp at the thermostat housing.
  7. Remove the radiator outlet hose from the thermostat housing. Proceed to step 11.

  8. Object Number: 1578327  Size: SH
  9. If the vehicle is equipped with a engine oil cooler, reposition the radiator outlet hose clamp at the thermostat housing.
  10. Remove the radiator outlet hose from the thermostat housing.

  11. Object Number: 1578329  Size: SH
  12. Reposition the surge tank outlet hose clamp at the thermostat housing.
  13. Remove the surge tank outlet hose from the thermostat housing.

  14. Object Number: 1713064  Size: SH
  15. Remove the thermostat housing cover bolts and cover.
  16. Remove the thermostat.
  17. Remove and discard the thermostat housing O-ring seal.

Installation Procedure


    Object Number: 1713064  Size: SH
  1. Install a NEW thermostat housing cover O-ring seal.
  2. Install the thermostat.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the thermostat housing cover bolts.
  5. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1578327  Size: SH
  6. If the vehicle is equipped with an engine oil cooler proceed with the following steps, otherwise proceed to step 9.
  7. Install the radiator outlet hose to the thermostat housing.
  8. Position the radiator outlet hose clamp at the thermostat housing.

  9. Object Number: 1578329  Size: SH
  10. Install the surge tank outlet hose to the thermostat housing.
  11. Position the surge tank outlet hose clamp at the thermostat housing. Proceed to step 13.

  12. Object Number: 1712757  Size: SH
  13. If the vehicle is not equipped an engine oil cooler, install the radiator outlet hose to the thermostat housing.
  14. Position the radiator outlet hose clamp at the thermostat housing.

  15. Object Number: 1713058  Size: SH
  16. Install the radiator outlet hose to the surge tank.
  17. Position the radiator outlet hose clamp at the surge tank.
  18. Fill the cooling system. Refer to Cooling System Draining and Filling .

Engine Coolant Thermostat Replacement LZ9

Removal Procedure


    Object Number: 1583645  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling .
  2. Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
  3. Reposition the radiator outlet hose clamp at the thermostat housing.
  4. Remove the radiator outlet hose from the thermostat housing.

  5. Object Number: 1556817  Size: SH
  6. Remove the thermostat housing bolt/stud.
  7. Remove the thermostat housing and gasket.
  8. Remove the thermostat.
  9. Clean the gasket surfaces.

Installation Procedure


    Object Number: 1556817  Size: SH
  1. Install a NEW thermostat.
  2. Position a NEW gasket and the thermostat housing to the engine block.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the thermostat housing bolt/stud.
  5. Tighten
    Tighten the bolt/stud to 10 N·m (89 lb in).


    Object Number: 1583645  Size: SH
  6. Install the radiator outlet hose to the thermostat housing.
  7. Position the radiator outlet hose clamp at the thermostat housing.
  8. Install the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
  9. Fill the cooling system. Refer to Cooling System Draining and Filling .
  10. Inspect the system for leaks.