How to Change the Thermostat in a Ford F-150

by Editorial TeamUpdated November 07, 2017

Items you will need

  • Mechanic's toolset, including a full socket set, wrenches and screwdrivers

  • Replacement thermostat, new or rebuilt

  • New gasket for thermostat

How to Change the Thermostat in a Ford F-150. The Ford F-150 is part of the "F Series," the moniker assigned to an entire succession of Ford trucks produced over the past 60 years. The current generation of the F-150, which debuted in 2004, is consider to be the best so far. The following is a beginners do-it-yourself project for the installation of a new thermostat on the 4.2L V6 engine.

Drain about half the coolant from the cooling system. Store the coolant in a sealable container.

Disconnect the upper radiator hose. Loosen and remove the bolts, then take out the water outlet connection.

Lift out the thermostat and the paper gasket, which is part of the assembly. Discard the used gasket.

Set the new thermostat in place with a new gasket. Note that the thermostat is indexed and must be correctly positioned.

Connect the water outlet adapter and secure it with the bolts. Tighten the bolts to 80 inch pounds. Reconnect the upper radiator hose.

Refill the coolant system to the proper levels with the recommended coolant. Start the engine and allow it to run for several minutes. Check for leaks and make the necessary adjustments. Add coolant as needed.


Outlet hoses slide onto fittings or connectors that grip the individual hose and hold it in place with a clamp. No special tools are required to remove or reconnect hoses. Label the hose and its connection before separating.


Ingesting coolant is often fatal. Reuse the coolant unless it is contaminated or old.

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