GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Replacement LD8

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure


    Object Number: 1664571  Size: SH
  1. Remove the air cleaner. Refer to Air Cleaner Assembly Replacement .
  2. Drain the cooling system. Refer to Cooling System Draining and Filling .
  3. Using the J 38185 , reposition the radiator outlet hose clamp at the thermostat housing.
  4. Remove the radiator outlet hose from the thermostat housing.

  5. Object Number: 611039  Size: SH
  6. Remove the thermostat housing bolts.

  7. Object Number: 611035  Size: SH
  8. Remove the thermostat housing, thermostat, and gasket from the water pump housing.
  9. Discard the old thermostat housing gasket.

Installation Procedure


    Object Number: 611035  Size: SH
  1. Install a NEW thermostat housing gasket into the water pump housing.
  2. Install the thermostat into the water pump housing.
  3. Install the thermostat housing.
  4. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 611039  Size: SH
  5. Install the thermostat housing bolts.
  6. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1664571  Size: SH
  7. Install the radiator outlet hose to the thermostat housing.
  8. Using the J 38185 , position the radiator outlet hose clamp at the thermostat housing.
  9. Fill the cooling system. Refer to Cooling System Draining and Filling .
  10. Install the air cleaner. Refer to Air Cleaner Assembly Replacement .

Engine Coolant Thermostat Replacement L26

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure


    Object Number: 1686393  Size: SH
  1. Remove the intake manifold cover. Refer to Intake Manifold Cover Replacement .
  2. Partially drain the cooling system. Refer to Cooling System Draining and Filling .
  3. Using J 38185 reposition the hose clamp at the thermostat housing.
  4. Remove the radiator inlet hose from the thermostat housing.

  5. Object Number: 1687997  Size: SH
  6. Remove the thermostat housing bolts and housing.

  7. Object Number: 1688001  Size: SH
  8. Remove the thermostat.
  9. Inspect and clean the thermostat housing mating surfaces.

Installation Procedure


    Object Number: 1688001  Size: SH
  1. Install the thermostat.
  2. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1687997  Size: SH
  3. Install the thermostat housing and bolts.
  4. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).


    Object Number: 1686393  Size: SH
  5. Install the radiator inlet hose to the thermostat housing.
  6. Using J 38185 position the hose clamp at the thermostat housing.
  7. Fill the cooling system. Refer to Cooling System Draining and Filling .
  8. Install the intake manifold cover. Refer to Intake Manifold Cover Replacement .