GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Catera 🢒 Engine 🢒 Engine Cooling 🢒 Engine Coolant Thermostat Replacement

Removal Procedure
  1. Drain the engine coolant. Refer to Cooling System Draining and Filling .
  2. Remove the intake plenum. Refer to Intake Plenum Replacement in Engine Mechanical.
  3. Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical.

    4. Object Number: 142121 Size: SH
  4. Remove the radiator inlet hose (1) from the thermostat outlet pipe.

    5. Object Number: 142122 Size: SH
  5. Remove the thermostat outlet pipe bolt (1).
  6. Remove the thermostat outlet pipe (2).

    7. Object Number: 142123 Size: SH
  7. Remove the O-ring seals from the thermostat outlet pipe.
  8. Discard the O-rings.

    9. Object Number: 142124 Size: SH
  9. Remove the thermostat with the housing:
    10. • Remove the bolts (1).
    • Tilt the rear of the thermostat housing upward.
    • Lift out the housing (2).
    • Remove the seal ring.
    • Discard the seal ring.

Installation Procedure

    Object Number: 142124 Size: SH
  1. Install the thermostat with the thermostat outlet housing (2):
    2. • Install a new seal ring.
    • Position the thermostat to the thermostat outlet housing.
    • Apply sealant GM P/N 12346004 (Canadian P/N 10953480) to the thermostat housing bolt threads.

    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.

    • Install the thermostat outlet housing bolts (1).

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


    Object Number: 142123 Size: SH
  2. Lubricate two new O-rings with coolant.
  3. Install the new O-rings in the thermostat outlet pipe.

    4. Object Number: 142122 Size: SH
  4. Install the thermostat outlet pipe (2).
  5. Install the thermostat outlet pipe bolt (1).

    6. Tighten
    Tighten the thermostat outlet bolt to 20 N·m (15 lb ft).


    Object Number: 142121 Size: SH
  6. Install the radiator inlet hose (1) to the thermostat outlet pipe.
  7. Install the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical.
  8. Install the intake plenum. Refer to Intake Plenum Replacement in Engine Mechanical.
  9. Fill the cooling system. Refer to Cooling System Draining and Filling .