Engine Coolant Thermostat Replacement 4.3L

1. Remove the air inlet duct.
2. Remove the necessary coolant from the radiator. Refer to Cooling System Draining and Filling .
3. Remove the upper radiator inlet hose.



4. Remove the coolant outlet bolts.



5. Remove the coolant outlet from the lower intake manifold.
6. Remove the thermostat gasket.



7. Remove the coolant thermostat.
8. Clean all the sealing surfaces of the coolant outlet.
9. Clean the sealing surface on the lower intake manifold.

Important: In order to prevent leakage, thoroughly clean all parts and sealing surfaces.

1. Install the coolant thermostat in the lower intake manifold.



2. Install a new gasket (if used). Otherwise, place a 3 mm (1/8 in) bead of RTV sealer (GM P/N 1052289, or equivalent) at the groove on the coolant outlet sealing surface.
3. Install the coolant outlet on the lower intake manifold.




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 attaching bolts.

Tighten
Tighten coolant outlet bolts to 19 N·m (14 lb ft).

5. Install the radiator inlet hose.
6. Fill the cooling system with specified coolant and concentration. Refer to Cooling System Draining and Filling .
7. Inspect all sealing surfaces for leaks after starting the engine. Refer to Cooling System Leak Testing .

Engine Coolant Thermostat Replacement 2.2L

1. Remove the necessary amount of coolant from the radiator. Refer to Cooling System Draining and Filling .
2. Remove the upper radiator inlet hose.
3. Remove the coolant outlet nuts.



4. Remove the thermostat housing from the engine.
5. Remove the thermostat gasket, if used.
6. Remove the coolant thermostat and O-ring seal.
7. Clean all of the parts.
8. Clean all of the sealing surfaces.

1. Install the thermostat and the O-ring seal to the engine.
2. Install the new thermostat gasket (if used). Otherwise, place a 3 mm (1/8 in) bead of RTV sealer (GM P/N 1052289, or equivalent) in the groove of the coolant outlet sealing surface.



3. Install the thermostat housing to the engine.

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 coolant outlet attaching nuts.

Tighten
Tighten the coolant outlet nuts to 10 N·m (89 lb in).

5. Install the upper radiator inlet hose.
6. Fill the cooling system with the specified coolant and concentration. Refer to Cooling System Draining and Filling .
7. Inspect all of the sealing surfaces and the connections for leaks after starting the engine. Refer to Cooling System Leak Testing .