GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Replacement LA1

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure

  1. Remove the air cleaner and duct assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls - 3.4L.
  2. Drain the coolant until the coolant level is below the thermostat. Refer to Cooling System Draining and Filling .
  3. Remove the crossover exhaust pipe. Refer to Exhaust Crossover Pipe Replacement in Engine Exhaust.
  4. Remove the radiator hose from the thermostat housing.

  5. Object Number: 30962  Size: SH
  6. Remove the thermostat housing bolts and clean any sealer from the bolt threads.
  7. Remove the thermostat housing and gasket.

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

Installation Procedure


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

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

  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 thermostat housing bolts.
  6. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

  7. Install the radiator hose to the thermostat housing.
  8. Install the crossover exhaust pipe. Refer to Exhaust Crossover Pipe Replacement in Engine Exhaust.
  9. Install the air cleaner and duct assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls - 3.4L.
  10. Fill the cooling system. Refer to Cooling System Draining and Filling .