GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Replacement 3.8L

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure


    Object Number: 308970  Size: SH
  1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical - 3.8L.
  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 water outlet housing.
  4. Remove the radiator inlet hose from the water outlet housing.

  5. Object Number: 153572  Size: SH
  6. Remove the water outlet housing bolt and stud.
  7. Remove the water outlet housing and gasket.

  8. Remove the thermostat.
  9. Inspect and clean the water outlet housing mating surfaces.

Installation Procedure


    Object Number: 153572  Size: SH
  1. Install the thermostat.
  2. Install the gasket and the water outlet housing.
  3. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  4. Install the water outlet housing bolt and stud to the water outlet housing.
  5. Tighten
    Tighten the water outlet housing bolt and stud to 27 N·m (20 lb ft).


    Object Number: 308970  Size: SH
  6. Install the radiator inlet hose to the water outlet housing.
  7. Use the J 38185 in order to reposition and install the hose clamp to the water outlet housing.
  8. Fill the cooling system. Refer to Cooling System Draining and Filling .
  9. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical - 3.8L.
  10. Inspect for leaks.

Engine Coolant Thermostat Replacement 3.1L

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure

  1. Remove the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.1L.
  2. Partially drain the cooling system. Refer to Cooling System Draining and Filling .
  3. Use the J 38185 in order reposition the hose clamp from the water outlet housing.
  4. Remove the radiator inlet hose from the water outlet housing.
  5. Remove the exhaust crossover pipe. Refer to Exhaust Crossover Pipe Replacement in Engine Exhaust.

  6. Object Number: 70064  Size: SH
  7. Remove the water outlet housing bolts.

  8. Object Number: 30962  Size: SH
  9. Remove the water outlet housing and gasket.

  10. Object Number: 30995  Size: SH
  11. Remove the thermostat.
  12. Clean the water outlet housing mating surfaces.

Installation Procedure


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

  2. Object Number: 30962  Size: SH
  3. Install the water outlet gasket and the water outlet housing.

  4. Object Number: 70064  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  5. Install the water outlet housing bolts.
  6. Tighten
    Tighten the water outlet housing bolts to 25 N·m (18 lb ft).

  7. Install the exhaust crossover pipe. Refer to Exhaust Crossover Pipe Replacement in Engine Exhaust.
  8. Install the radiator inlet hose to the water outlet housing.
  9. Use the J 38185 in order reposition and install the hose clamp to the water outlet housing.
  10. Install the air cleaner intake duct. Refer to Air Cleaner Inlet Duct Replacement in Engine Controls - 3.1L.
  11. Fill the cooling system. Refer to Cooling System Draining and Filling .
  12. Inspect for leaks.