Thermostat Housing: Service and Repair

REMOVAL PROCEDURE





1. Drain the coolant from the radiator. Refer to Draining and Filling Cooling System.
2. Remove the compressor. Refer to Compressor Replacement (7.4L) or Compressor Replacement (6.5L) in Heating and Air Conditioning.
3. Remove the crankcase depression regulator valve.
4. Remove the generator upper bracket.
5. Disconnect the bypass hose.
6. Disconnect the upper radiator hose. Refer to Radiator Hose Replacement (5.0L) or Radiator Hose Replacement (5.7L) or Radiator Hose Replacement (6.5L Diesel).
7. Disconnect the heater hose. Refer to Heater Hoses Replacement in Heating and Air Conditioning.
8. Remove the studs and the bolts.
9. Remove the coolant crossover housing assembly (4) from the vehicle. The thermostats (2) and the coolant outlet (1) attach to the crossover housing assembly, along with the thermostat bypass nipple (5).
10. Clean the crossover housing sealing surfaces.

INSTALLATION PROCEDURE





1. Install the new gaskets (3).
2. Install the coolant crossover housing assembly (4).

NOTICE: Refer to Fastener Notice in Service Precautions.

3. Install the studs and the bolts.
^ Tighten the studs and the bolts to 42 Nm (31 ft. lbs.).
4. Connect the heater hose. Refer to Heater Hoses Replacement in Heating and Air Conditioning.
5. Connect the upper radiator hose. Refer to Radiator Hose Replacement (5.0L) or Radiator Hose Replacement (5.7L) or Radiator Hose Replacement (6.5L Diesel).
6. Connect the bypass hose.
7. Install the generator upper bracket.
8. Install the compressor. Refer to Compressor Replacement (7.4L) or Compressor Replacement (6.5L) in Heating and Air Conditioning.
9. Install the crankcase depression regulator valve.
10. Fill the cooling system with coolant. Refer to Draining and Filling Cooling System.
11. Start the engine. Run the engine, with the surge tank cap removed, until the upper radiator hose becomes hot. This indicates that the thermostat is open.
12. Attach the surge tank cap to the surge tank. Make sure that the cap arrows line up with the overflow tube.
13. Inspect the cooling system for leaks.