Thermostat Housing: Service and Repair

Thermostat Housing Replacement (L61)

^ Tools Required
- J 38185 Hose Clamp Pliers

Removal Procedure





1. Notice: The thermostat will not function correctly once it is contacted by oil. If oil is found in the cooling system, it must be flushed and the thermostat's cartridge replaced.

Remove the coolant cap from the surge tank.
2. Place a coolant container under the radiator drain valve at the right hand side of the radiator tank.
3. Using a flat-bladed screwdriver, open the valve and drain the coolant.
4. Raise the vehicle on a hoist.





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

Drain the coolant from the engine block at the water pump drain. After the coolant has drained, tighten the drain bolt.
6. Lower the vehicle.





7. Disconnect the radiator hose and clamp from the thermostat pipe assembly using the J 38185, or equivalent.





8. Disconnect the surge tank return hose and clamp from the thermostat housing pipe.
9. Remove the attachment bolt from the thermostat bracket assembly to thermostat pipe assembly near the front of the engine.





10. Remove the exhaust heat shield bolts.
11. Remove the exhaust heat shield.
12. Disconnect the electrical connector at the coolant temperature sensor.
13. Disconnect the O2 sensor connector and clip from the bracket.





14. Disconnect the heater inlet and outlet hoses and clamps at the thermostat housing pipes.





15. Remove the thermostat housing bolts to the engine.

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

Remove the water transfer pipe from the thermostat housing.
17. Remove the thermostat housing assembly from the vehicle.





18. Remove the water transfer pipe O-seals and discard.
19. Remove the thermostat housing cover bolts and cover.
20. Remove and discard the thermostat housing O-seal.
21. Remove the thermostat cartridge and inner sleeve from the thermostat housing.
22. Remove all debris and thread sealant from the engine coolant temperature sensor and bolt holes if the housing is being re-used.

Installation Procedure





1. Install the thermostat cartridge into the thermostat housing while aligning the cartridge tangs up with the thermostat housing bolt holes. This will assure the inner sleeve can be completely installed.





2. Align and insert the inner sleeve notch into the thermostat housing. If the inner sleeve notch is not properly positioned, the sleeve will not completely seat into the housing.





3. Install a new thermostat housing cover seal into the recess groove.

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

Install the thermostat housing cover bolts.
^ Tighten the thermostat housing cover-to-thermostat housing bolts to 10 Nm (89 inch lbs.).
5. Install a new thermostat housing to engine seal onto the thermostat housing.
6. Load the thermostat housing assembly into position while the vehicle is lowered.
7. Raise the vehicle. Refer to Vehicle Lifting.





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

Install new O-seals onto the water feed pipe.

9. Important: Lubricate the O-rings with coolant ONLY.

Install the water feed pipe into the thermostat housing aligning locator tab.
10. Align the water pipe to water pump.
11. Seat the water feed O-seal by pushing inward toward the water pump. Take care not to tear or damage the O-ring.
12. Lower the vehicle.





13. Position the thermostat housing against the engine. Be sure that the thermostat housing pipe is properly positioned against the support bracket near the front of the engine.
14. Install the thermostat housing to block bolts.
^ Tighten the thermostat housing-to-block bolts to 10 Nm (89 inch lbs.).
15. Install the thermostat pipe bracket-to-engine bolt.
^ Tighten the thermostat pipe bracket-to-cylinder head bolt to 8 Nm (71 inch lbs.).





16. Connect the electrical connector to coolant sensor.
17. Connect the O2 sensor connector and re-attach the connector to the bracket.





18. Connect the heater inlet and outlet hoses to the thermostat housing and reposition the clamps.





19. Connect the lower radiator hose and clamp.
20. Connect the surge tank return hose to the thermostat pipe.





21. Install the exhaust manifold heat shield.
22. Install the exhaust manifold shield bolts.
^ Tighten the exhaust manifold heat shield bolts to 23 Nm (17 ft. lbs.).





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

Verify the drain valves at the radiator and water pump are closed.





24. Fill the engine coolant.
25. Verify the repair and inspect for any leaks.