Thermostat: Service and Repair

Thermostat - 4.6L, 5.4L and 6.8L











Removal and Installation
1. Drain the engine cooling system. For additional information, refer to Cooling System Draining, Filling and Bleeding.
2. Remove the air cleaner outlet pipe. For additional information, refer to Fuel Delivery and Air Induction.
3. If servicing the thermostat housing, disconnect the upper radiator hose.
4. Remove the 2 bolts and position the thermostat housing aside. Remove the thermostat and discard the O-ring seal.
^ Inspect and clean the sealing surfaces with metal surface prep. Follow the directions on the packaging.
^ Install a new O-ring seal.
^ To install, tighten to 25 Nm (18 lb-ft).
5. To install, reverse the removal procedure.
6. Fill and bleed the engine cooling system.