The Lincoln Navigator has the distinction of being the first full-size SUV offered by a luxury automaker. Navigator was the icon model in the late 1990s, the 2002, which concluded Navigator's first generation. This is a do-it-yourself project for the removal and installation thermostat on the 4.6L and 5.4L SOHC engines.
Drain enough coolant from the engine to bring the level below that of the thermostat. Store the coolant in a container that can be securely sealed.
Take the upper radiator hose from the water outlet adapter. Remove the upper mounting bracket for the power steering reservoir. Loosen and then remove the bolts on the water outlet adapter, and then remove the adapter.
Lift out the thermostat and the O-ring seal. Remove the O-ring seal and throw it away.
Set a new O-ring in place on the thermostat. Place the thermostat in position and then replace the water outlet adapter. Torque the water outlet adapter bolts to 18 foot pounds.
Replace the upper mounting bracket for the power steering reservoir. Torque the two upper bolts to 13 foot pounds and the lower bolt to 8 foot pounds.
Connect the upper radiator hose to the water outlet adapter. Refill the cooling system with the recommended coolant.
Start the engine and check for leaks. Turn off the engine and add coolant as needed.
