Engine Coolant Thermostat Replacement 4.2L Engine

Tools Required

J 38185 Hose Clamp Pliers

1. Remove the necessary coolant from the radiator. Refer to Cooling System Draining and Filling .
2. Remove the generator. Refer to Generator Replacement .



3. Loosen the outlet hose clamp at the thermostat housing (1). Remove the outlet hose from the thermostat housing.



4. Remove the thermostat housing bolts.
5. Remove the thermostat housing from the engine block.
6. Clean all of the surfaces of the thermostat housing.
7. Clean the sealing surface of the engine block.

1. Install the thermostat housing to the engine block.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the thermostat housing bolts.

Tighten
Tighten the bolts to 10 N·m (89 lb in).

3. Lubricate the inner diameter of the radiator hose with engine coolant.



4. Install the outlet hose to the thermostat housing (1). Secure the hose with the clamp.
5. Install the generator. Refer to Generator Replacement .
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.

Engine Coolant Thermostat Replacement 5.3L Engine

Important: The thermostat is not serviceable separately. The water pump inlet and thermostat must be replaced as an assembly.

1. Remove the radiator outlet hose. Refer to Radiator Outlet Hose Replacement .
2. Remove the water pump inlet bolts.
3. Remove the water pump inlet and thermostat from the water pump.

1. Install the thermostat and thermostat housing to the water pump.

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.

2. Install the thermostat housing bolts.

Tighten
Tighten the bolts to 15 N·m (11 lb ft).

3. Install the radiator outlet hose. Refer to Radiator Outlet Hose Replacement .