GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Replacement 2.2L

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

    Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

  1. Disconnect the negative battery cable.
  2. Drain the coolant to level below the thermostat. Recover the coolant. Refer to Cooling System Draining and Filling .

  3. Object Number: 25794  Size: SH
  4. Remove the radiator coolant outlet pipe attaching bolts.

  5. Object Number: 25792  Size: SH
  6. Remove the coolant outlet.

  7. Object Number: 25790  Size: SH
  8. Remove the thermostat.
  9. Clean the mating surfaces of the radiator outlet and the radiator outlet pipe.

Installation Procedure


    Object Number: 25790  Size: SH
  1. Install the thermostat.

  2. Object Number: 25792  Size: SH
  3. Install the coolant outlet.
  4. 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 coolant outlet attaching bolts.
  6. Tighten
    Tighten the coolant outlet bolts to 14 N·m (124 lb in).


    Object Number: 25794  Size: SH
  7. Refill the engine coolant. Refer to Cooling System Draining and Filling .
  8. Connect the negative battery cable.
  9. Inspect for leaks.

Engine Coolant Thermostat Replacement 2.4L

Removal Procedure 2.4L

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

    Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

  1. Disconnect the negative battery cable.
  2. Drain the coolant until the coolant level is below the thermostat. Recover the coolant. Refer to Cooling System Draining and Filling .

  3. Object Number: 25787  Size: SH
  4. Remove the exhaust manifold heat shield.
  5. Remove the radaitor outlet bolts (1).
  6. Remove cover to the outlet pipe through exhaust manifold runners.
  7. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

  8. Object Number: 25807  Size: SH
  9. Disconnect the radiator outlet hose (1) and the clamp (2) from the radiator outlet pipe (3).

  10. Object Number: 25789  Size: SH
  11. Remove the radiator outlet pipe (1) to oil pan (2) bolt (3).
  12. Remove the cover to the outlet pipe bolt.

  13. Object Number: 25784  Size: SH
  14. Remove the thermostat (2) and the seal (1) from the outlet pipe (3).
  15. Clean the mating surfaces of the radiator outlet pipe and the coolant pump cover.

Installation Procedure


    Object Number: 25784  Size: SH
  1. Install the thermostat (2) and the seal (1) to the radiator outlet pipe (3).

  2. Object Number: 25789  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.

  3. Install the radiator outlet pipe (1) to oil pan (2) bolt (3).
  4. Tighten
    Tighten the outlet pipe to oil pan bolt to 26 N·m (19 lb ft).


    Object Number: 25807  Size: SH
  5. Connect the outlet pipe to the oil pan bolt.
  6. Tighten
    Tighten the oil pan to 26 N·m (19 lb ft).

  7. Install the radiator hose (1) and clamp (2) to the outlet pipe (3).
  8. Lower the vehicle.

  9. Object Number: 25787  Size: SH
  10. Install the cover (2) to the outlet pipe bolt (1) through the exhaust manifold runner.
  11. Install the exhaust manifold heat shield.
  12. Fill the cooling system. Refer to Cooling System Draining and Filling .
  13. Connect the negative battery cable.
  14. Inspect for leaks.