- Remove the necessary coolant from the radiator.
- Remove the alternator, as outlined in the Engine Electrical Section.
- Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
- Remove the thermostat housing bolts.
- Remove the thermostat housing from the engine block.
- Clean all of the surfaces of the thermostat housing.
- Clean the sealing surface of the engine block.
- Install the thermostat housing to the engine block.
- Install the thermostat housing bolts and tighten to 89 inch lbs. (10 Nm).
- Lubricate the inner diameter of the radiator hose with engine coolant.
- Install the outlet hose to the thermostat housing. Secure the hose with the clamp.
- Install the alternator.
- Fill the cooling system with specified coolant and concentration.
- Inspect all sealing surfaces for leaks after starting the engine.
5.3L & 6.0L Engines
The thermostat is not serviceable separately. The water pump inlet and thermostat must be replaced as an assembly.
- Drain the cooling system to a level below the thermostat.
- Remove the radiator outlet hose.
- Remove the water pump inlet bolts.
- Remove the water pump inlet and thermostat from the water pump.
- Install the thermostat and thermostat housing to the water pump.
- Install the thermostat housing bolts. Tighten the bolts to 11 ft. lbs. (15 Nm).
- Install the radiator outlet hose.
- Properly fill the engine cooling system and check for leaks.