Thermostat: Service and Repair

Removal Procedure





1. Remove the air cleaner and the duct assembly. Refer to Air Cleaner Assembly Replacement.
2. Partially drain the coolant. Refer to Draining and Filling Cooling System.
3. Remove the surge tank. Refer to Surge Tank (Diesel) Replacement.
4. Disconnect the radiator hose from the thermostat housing.





5. Remove the bolts attaching the thermostat housing to the thermostat.
6. Remove the thermostat housing.
7. Remove the thermostats.
8. Clean the gasket mating surfaces.


Installation Procedure

Notice: Refer to Coolant Addition Notice in Service Precautions.

Important: Thermostats must be replaced in pairs.





1. Install the thermostats.
2. Install the thermostat housing to the intake manifold.

Notice: Refer to Fastener Notice in Service Precautions.

3. Install the bolts to the housing.
^ Tighten the bolts to 42 Nm (31 ft. lbs.).





4. Connect the radiator hose to the thermostat housing.
5. Install the surge tank. Refer to Surge Tank (Diesel) Replacement.
6. Install the air cleaner and the duct. Refer to Air Cleaner Assembly Replacement.

Important: In order to properly fill a system that has been completely drained, use the air bleed vents, located on the thermostat housing.

7. Refill the cooling system. Refer to Draining and Filling Cooling System.
8. Bleed the air from the cooling system.
9. Inspect the thermostat housing and the gasket for coolant leaks. Refer to Cooling System Leak Testing (Radiator Leak Test).