Thermostat: Service and Repair

WARNING: DO NOT LOOSEN THE RADIATOR DRAIN WITH THE SYSTEM HOT AND PRESSURIZED BECAUSE SERIOUS BURNS FROM THE COOLANT CAN OCCUR.

NOTE: When servicing the thermostat, do not allow coolant to drip onto the accessory drive belt and/or accessory drive pulleys. If coolant does contact the drive belt or pulleys, flush them with clean water.

Do not waste reusable coolant. If the solution is clean and being drained only to service the cooling system, drain the coolant into a clean container for reuse.

REMOVAL
1. Drain the coolant from the radiator until the level is below the thermostat housing.
2. Disconnect the coolant temperature sensor wire connector from the sensor.
3. Remove the spark plug wire holder from the top of the thermostat housing. Place shop towels on belts and pulleys.
4. Remove thermostat housing Leave upper radiator hose connected.
5. Remove thermostat.

Fig. 17 Thermostat Housing 3.0L - Late:

6. Check thermostat well and housing ports for blockage. Repair as necessary.
7. Clean gasket surfaces.

INSTALLATION

NOTE: The thermostat has an air bleed valve. When installing the thermostat, position the valve to the back of the thermostat well. This is the highest point of the well which is where air will settle in.

1. Install the thermostat with the air bleed valve to the rear of the thermostat well and the flat disk to the bottom of the thermostat well.
2. Install the thermostat housing. Tighten the mounting bolts to 12 Nm 9 ft.lbs.
3. Close radiator drain and remove hose.
4. Fill and bleed the cooling system see Cooling System Section Filling and Bleeding Procedures.