How to Change the Thermostat in a Ford Mustang

by Contributor

If you drive one of Ford's most popular and recognizable models, the Mustang, and notice heater or engine temperature problems, chances are good you'll need to replace the thermostat. Luckily, changing the thermostat in a Ford Mustang doesn't require a lot of time; in less than an hour, you can be back on the road.

Lift up the front end of your Ford Mustang with a jack and lower it onto jack stands, or use wheel ramps. Unscrew the radiator cap and open the drain plug at the bottom of the radiator. Drain the coolant into a suitable container. Reuse this coolant if relatively new and clean.

Follow the upper radiator hose to the thermostat housing located at the top of the engine next to the alternator. Use vise-grip pliers to loosen the hose clamp at the end of the radiator hose and pull the hose off the thermostat housing.

Use a 10mm socket or wrench to remove the two bolts on either side of the thermostat housing to remove the thermostat housing cover. Pull off the cover to expose the thermostat. Clean any old gasket residue from inside the thermostat housing cover.

Remove the old thermostat by prying up with a screwdriver or pulling it out with a pair of pliers. Insert the new thermostat with the spring-side facing into the engine. Install the new o-ring gasket. Make sure the gasket is seated correctly for proper sealing.

Reattach the thermostat housing cover and the radiator hose. Tighten the thermostat housing bolts to 18 foot/pounds. with a torque wrench. Fill the radiator with reserve or new coolant.

Start your Mustang and allow it to run with the radiator cap off for several minutes. Replace the cap and run the Mustang until it reaches normal operating temperature. Drive a short distance, then park and allow the engine to cool. Check the level of the coolant. Add more coolant if necessary.

Tip

  • check Save a step and simply remove the bolts from the thermostat housing cover and pull off the cover with the radiator hose still attached, if desired.

Warning

  • close Don't drain the coolant from your Ford Mustang while the engine is hot.

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