Thermostat Housing: Service and Repair

Thermostat Housing Crossover Replacement (6.6L (LLY) Engine)

Removal Procedure





1. Remove the intake manifold cover.
2. Drain the cooling system.
3. Disconnect the negative battery cables.
4. Remove the upper fan shroud.
5. Remove the drive belt.
6. Disconnect the Air Conditioning (A/C) compressor clutch electrical connector (5).
7. Disconnect the A/C cut out switch electrical connector.





8. Remove the A/C compressor bolts.
9. Reposition the A/C compressor, with the hoses attached, to the right side of the engine compartment.





10. Remove the generator positive cable to generator nut.
11. Remove the positive cable from the generator.
12. Remove the clip holding the positive cable to the engine front cover.
13. Remove the battery positive cable junction block to power steering pump bolt (1).
14. Move the generator positive cable and the junction block bracket aside.





15. Disconnect the generator electrical connector.
16. Disconnect the Engine Coolant Temperature (ECT) sensor electrical connector.





17. Remove the power steering pump bracket bolts.
18. Reposition the power steering pump bracket and secure to the side.
^ Do not remove the power steering pump from the bracket.
^ The hoses and battery cables can remain on the power steering pump.





19. Remove the heater outlet hose bracket bolt from the generator bracket.
20. Remove the idler pulley.
21. Remove the generator bracket bolts.
22. Remove the generator bracket and position to the side.
^ The generator does not require removal.
^ The drive belt tensioner does not require removal.

23. Remove the oil fill tube.
24. Remove the water outlet.





25. Reposition the Exhaust Gas Recirculation (EGR) hose clamp at the EGR coolant pipe.
26. Remove the EGR coolant pipe bolt.
27. Remove the EGR coolant pipe with O-ring seal from the crossover.





28. Reposition the turbocharger coolant return pipe hose clamp.
29. Remove the turbocharger coolant return pipe hose.





30. Remove the fuel line bracket bolt at the thermostat housing crossover.
31. Remove the cooling fan pulley.





32. Remove the water pump inlet pipe bolts.





33. Remove the thermostat housing bolts and nuts.
34. Remove the thermostat housing, with the bypass pipe.
35. Remove and discard the thermostat bypass pipe to water pump O-ring seal.
36. Remove and discard the thermostat housing gaskets.
37. If necessary, perform the following steps:
1. Remove the thermostat bypass pipe from the thermostat housing.
2. Remove and discard the thermostat bypass pipe O-ring seal.
3. Remove the thermostat cover bolts and cover.
4. Remove the thermostats.
5. Remove and discard the thermostat seals.

38. If required, clean and inspect the thermostat housing.

Installation Procedure





1. If necessary, perform the following steps:
1. Install NEW seals to the thermostats.
2. Install the thermostats.

3. Notice: Refer to Fastener Notice in Service Precautions.

Install the thermostat cover and bolts.
Tighten the bolts to 21 Nm (15 ft. lbs.).
4. Install a NEW O-ring seal to the thermostat bypass pipe.
5. Install the thermostat bypass pipe to the thermostat housing.
2. Install a NEW thermostat bypass pipe to water pump O-ring seal.
3. Install the thermostat housing using NEW gaskets.
4. Install the thermostat housing bolts and nuts
Tighten the bolts/nuts to 21 Nm (15 ft. lbs.).





5. Install the water pump inlet pipe bolts.
Tighten the bolts to 21 Nm (15 ft. lbs.).
6. Install the cooling fan pulley.





7. Install the fuel line bracket bolt at the thermostat housing crossover.
Tighten the bolt to 21 Nm (15 ft. lbs.).





8. Install the turbocharger coolant return pipe hose.
9. Position the turbocharger coolant return pipe hose clamp.





10. Install the EGR coolant pipe with O-ring seal to the crossover.
11. Install the EGR coolant pipe bolt.
Tighten the bolt to 25 Nm (18 ft. lbs.).
12. Position the EGR hose clamp at the EGR coolant pipe.
13. Install the water outlet.
14. Install the oil fill tube.





15. Position the generator bracket.
16. Install the generator bracket bolts.
Tighten the bolt to 50 Nm (37 ft. lbs.).
17. Install the idler pulley.
Tighten the bolt to 43 Nm (32 ft. lbs.).
18. Install the heater outlet hose bracket bolt to the generator bracket.
Tighten the bolt to 21 Nm (15 ft. lbs.).





19. Position the power steering pump bracket.
20. Install the power steering pump bracket bolts.
Tighten the bolt to 46 Nm (34 ft. lbs.).





21. Position the generator positive cable and the junction block bracket.
22. Install the battery positive cable junction block to power steering pump bolt (1).
Tighten the bolt to 9 Nm (80 inch lbs.).
23. Install the clip holding the positive cable to the engine front cover.
24. Install the positive cable to the generator.
25. Install the generator positive cable to generator nut.
Tighten the nut to 9 Nm (80 inch lbs.).





26. Connect the ECT sensor electrical connector.
27. Connect the generator electrical connector.





28. Position the A/C compressor, with the hoses attached.
29. Install the A/C compressor bolts.
Tighten the bolts to 50 Nm (37 ft. lbs.).





30. Connect the A/C cut out switch electrical connector.
31. Connect the A/C compressor clutch electrical connector (5).
32. Install the drive belt.
33. Install the upper fan shroud.
34. Connect the negative battery cables.
35. Fill the cooling system.
36. Install the intake manifold cover.