GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Housing Replacement LH2

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure

  1. Drain the cooling system. Refer to Cooling System Draining and Filling .
  2. Remove the air outlet duct in order to gain access to the thermostat housing. Refer to Air Cleaner Inlet Duct Replacement .

  3. Object Number: 1201091  Size: SH
  4. Remove the heater hose from the thermostat housing using a J 38185 .
  5. Remove the coolant radiator hose from the thermostat housing. Refer to Coolant Bypass Hose Replacement .
  6. Remove the thermostat housing bolts.
  7. Remove the thermostat housing (1) with thermostat from the engine front cover.
  8. Remove the thermostat (3) and seal ring (2) and discard the seal ring.

Installation Procedure


    Object Number: 1201091  Size: SH
  1. Install a new seal ring (2) on the thermostat (3).
  2. Install the thermostat and new seal ring into the thermostat housing (1).
  3. Install the thermostat housing (1) with the thermostat (3) assembly to the engine front cover.
  4. Notice: Refer to Fastener Notice in the Preface section.

  5. Install the thermostat housing bolts.
  6. Tighten
    Tighten the thermostat housing bolts to 20 N·m (15 lb ft).

  7. Position the radiator hose over to the thermostat housing and reposition the clamp using the J 38185 .
  8. Install the heater hose to the thermostat housing using J 38185 .
  9. Install the air outlet duct. Refer to Air Cleaner Inlet Duct Replacement .
  10. Fill the cooling system. Refer to Cooling System Draining and Filling .

Engine Coolant Thermostat Housing Replacement LC3

Removal Procedure


    Object Number: 1688440  Size: SH
  1. Drain the cooling system. Refer to Cooling System Draining and Filling .
  2. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  3. Remove the radiator hose from the thermostat housing. Refer to Radiator Outlet Hose Replacement .
  4. Remove the heater hose from the thermostat housing.
  5. Remove the thermostat housing bolts.
  6. Remove the thermostat housing (1) with thermostat (3), from the water housing.
  7. Remove and discard the seal ring (2).
  8. Remove the thermostat from the thermostat housing.

Installation Procedure


    Object Number: 1688440  Size: SH
  1. Clean the thermostat housing and water housing sealing surfaces.
  2. Install the thermostat (3) to the thermostat housing (1).
  3. Install the NEW seal (2) to the thermostat housing.
  4. Install the thermostat housing (1) with the thermostat (3) and the seal (2) to the water housing.
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the thermostat housing bolts.
  7. Tighten
    Tighten the thermostat housing bolts to 10 N·m (89 lb in).

  8. Install the heater hose to the thermostat housing.
  9. Install the radiator hose to the thermostat housing. Refer to Radiator Outlet Hose Replacement .
  10. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement .
  11. Fill the cooling system. Refer to Cooling System Draining and Filling .