Thermostat: Service and Repair

Thermostat Replacement

Removal Procedure

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.





1. Drain the coolant.





2. Remove the exhaust heat shield bolts.
3. Remove the exhaust heat shield.
4. Raise the vehicle.





Important: A drain plug has been provided at the bottom of the water pump assembly for additional coolant drainage from the engine block and water pump.

5. Drain the coolant from the water pump drain plug.





6. Remove the thermostat cover bolts from the thermostat housing.
7. Remove and discard the thermostat housing O-seal.





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

8. Remove the water pipe from the water pump assembly.
9. Remove and discard the seals from the water pipe.
10. Remove the inner thermostat sleeve.
11. Remove the thermostat assembly.

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.





Important: The water feed pipe seals can be slightly lubricated with silicone gel to aid during installation.

3. Install a new O-seal on the water pipe.
4. Position the water pipe into the water pump assembly.
5. Seat the water feed O-seal by pushing and twisting toward the water pump. Take care not to tear or damage the O-ring.





6. Install the thermostat housing cover to the water pipe. The water feed pipe has a locating tab to assure proper alignment.
7. Install a new thermostat housing cover seal into the recess groove.
8. Position the thermostat housing cover into position.

Notice: Refer to Fastener Notice in Service Precautions.

9. Install the thermostat housing cover bolts.
^ Tighten the thermostat housing cover-to-thermostat housing bolts to 10 Nm (89 inch lbs.).





10. Lower the vehicle.
11. Install the exhaust manifold heat shield.
12. Install the exhaust manifold heat shield bolts.
^ Tighten the exhaust manifold heat shield bolts to 23 Nm (17 ft. lbs.).





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

13. Verify the drain valve at the radiator and the water pump are closed.





14. Fill the engine coolant.
15. Verify the repair and inspect for any leaks.