GM Service Manual Online
For 1990-2009 cars only

Engine Coolant Thermostat Replacement 2.2L

Removal Procedure

    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. Refer to

    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.

    in General Information.
  2. Drain and recover the coolant until the coolant level is below the thermostat. Refer to Cooling System Draining and Filling .

  3. Object Number: 59012  Size: SH
  4. Disconnect the radiator outlet hose from the coolant outlet.
  5. Remove the coolant outlet attaching bolts.
  6. Remove the coolant outlet.
  7. Remove the thermostat.
  8. Clean the gasket mating surfaces of the coolant outlet and the coolant outlet pipe.

Installation Procedure


    Object Number: 59012  Size: SH
  1. Install the thermostat.
  2. Install the coolant outlet.
  3. Install the coolant outlet attaching bolts.
  4. Tighten
    Tighten the coolant outlet bolts to 14 N·m (124 lb in).

    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. Connect the radiator outlet hose and the clamp to the coolant outlet.
  6. Refill the engine coolant. Refer to Cooling System Draining and Filling .
  7. Connect the negative battery cable.
  8. Tighten
    Tighten the negative battery cable bolt to 15 N·m (11 lb in).

  9. Start the engine. After the engine reaches normal operating temperature, check for coolant leaks.

Engine Coolant Thermostat Replacement 3.1L

Removal Procedure

    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. Refer to

    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.

    in General Information.
  2. Drain the coolant to a level below the thermostat. Recover the coolant. Refer to Draining and Filling Cooling System .
  3. Remove the air inlet to the throttle body. Refer to Air Inlet Replacement in Engine Controls.

  4. Object Number: 25993  Size: SH
  5. Disconnect the surge tank inlet pipe from the thermostat housing.
  6. If the coolant outlet is being replaced, disconnect the radiator inlet hose from the coolant outlet.

  7. Object Number: 30962  Size: SH
  8. Remove the 2 bolts from the coolant outlet.
  9. Remove the coolant outlet.

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

Installation Procedure


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

  2. Object Number: 30962  Size: SH
  3. Install the coolant outlet to the thermostat housing.
  4. Install the coolant outlet bolts.
  5. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

    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.

  6. Install the radiator inlet hose to the coolant outlet, if the hose was removed.

  7. Object Number: 25993  Size: SH
  8. Install the surge tank inlet pipe to the thermostat housing.
  9. Install the air inlet to the throttle body. Refer to Air Inlet Replacement in Engine Controls.
  10. Refill the coolant. Refer to Draining and Filling Cooling System .
  11. Connect the negative battery cable.
  12. Tighten
    Tighten the negative battery cable bolt to 15 N·m (11 lb ft).

  13. Start the engine. After the engine reaches normal operating temperature, check for coolant leaks.