Thermostat Housing: Service and Repair

Engine Coolant Thermostat Housing Replacement (RPO LSJ)

Removal Procedure




1. Drain the cooling system. Refer to Draining and Filling Cooling System (2.0L (LSJ)) Draining and Filling Cooling System (2.2L (L61), 2.4L (LE5)) Draining and Filling Cooling System (GE 47716 Fill).

Important: A drain has been provided at the bottom of the water pump for engine block coolant drainage.

2. Drain the coolant from the engine block at the water pump drain. After the coolant has drained, tighten the drain bolt.
3. Lower the vehicle.
4. Remove the front heated oxygen sensor (HO2S) electrical connector clip from the thermostat housing.




5. Remove the positive crankcase ventilation (PCV) vent tube/hose bolt (4) and nuts (2, 5).
6. Reposition the PCV vent tube/hose clamps (1, 3).
7. Remove the PCV vent tube/hose from the air cleaner outlet duct, and the camshaft cover.
8. Remove the PCV vent tube/hose from the engine.




9. Reposition the radiator outlet hose clamp at the thermostat cover.
10. Remove the radiator outlet hose from the thermostat cover.




11. Reposition the radiator surge tank outlet hose clamp (1) at the thermostat cover.
12. Remove the radiator surge tank outlet hose from the thermostat cover.
13. Reposition the oil cooler inlet and outlet hose (2, 3) clamps at the thermostat cover.
14. Remove the oil cooler inlet and outlet hoses from the thermostat cover.




15. Remove the exhaust heat shield studs (2).
16. Remove the exhaust heat shield (1).




17. Reposition the heater inlet and outlet hose clamps at the thermostat housing pipes.
18. Disconnect the heater inlet (1) and outlet (2) hoses from the thermostat housing pipes.
19. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.




20. Remove the thermostat housing bolts.

Important: Twist the water transfer pipe while pulling in order to remove it from the water pump.

21. Remove the thermostat housing from the vehicle.
22. Remove the water transfer pipe from the thermostat housing, if necessary.
23. Remove and discard the water transfer pipe O-ring seals, if necessary.
24. Remove the thermostat cover bolts and cover, if necessary.
25. Remove the thermostat, if necessary.
26. Remove and discard the thermostat cover O-ring seal, if necessary.

Installation Procedure




1. Install a NEW thermostat cover O-ring seal into the recess groove.
2. Install the thermostat, if necessary.

Notice: Refer to Fastener Notice.

3. Install the thermostat cover bolts, if necessary.

Tighten the bolts to 10 N.m (89 lb in).

4. Install a NEW thermostat housing to engine gasket onto the thermostat housing.
5. Load the thermostat housing assembly into position.

Important: The water feed pipe seals can be lightly lubricated with coolant to aid during installation.

6. Install NEW O-ring seals onto the water feed pipe.

Important: Lubricate the O-rings with coolant ONLY.

7. Install the water feed pipe into the thermostat housing aligning locator tab.
8. Align the water pipe to water pump.
9. Seat the water feed O-ring seal by pushing inward toward the water pump. Take care not to tear or damage the O-ring.
10. Position the thermostat housing against the engine.
11. Install the thermostat housing bolts.

Tighten the bolts to 10 N.m (89 lb in).

12. Lower the vehicle.




13. Connect the heater inlet (1) and outlet (2) hoses to the thermostat housing pipes.
14. Position the heater inlet and outlet hose clamps at the thermostat housing pipes.




15. Install the exhaust heat shield (1).
16. Install the exhaust heat shield studs (2).

Tighten the studs to 22 N.m (16 lb ft).




17. Install the oil cooler inlet and outlet hoses to the thermostat cover.
18. Position the oil cooler inlet and outlet hose (2, 3) clamps at the thermostat cover.
19. Install the radiator surge tank outlet hose to the thermostat cover.
20. Position the radiator surge tank outlet hose clamp (1) at the thermostat cover.




21. Install the radiator outlet hose to the thermostat cover.
22. Position the radiator outlet hose clamp at the thermostat cover.




23. Install the PCV vent tube/hose to the engine.
24. Install the PCV vent tube/hose to the air cleaner outlet duct, and the camshaft cover.
25. Position the PCV vent tube/hose clamps (1, 3).
26. Install the PCV vent tube/hose bolt (4) and nuts (2, 5).

Tighten the bolt/nuts to 10 N.m (89 lb in).

27. Connect the front HO2S electrical connector clip to the thermostat housing.





Important: The vehicle must be level when filling the cooling system.

28. Verify the drain valves at the radiator and water pump are closed.
29. Fill the cooling system. Refer to Draining and Filling Cooling System (2.0L (LSJ)) Draining and Filling Cooling System (2.2L (L61), 2.4L (LE5)) Draining and Filling Cooling System (GE 47716 Fill).
30. Lower the vehicle.
31. Verify the repair and inspect for any leaks.