The engine temperature in a Ford F-150 is regulated by a thermostat. A faulty thermostat will stick and cause the coolant to back up into the radiator. Replacing the thermostat will help to ensure the truck stays cool and the coolant flows through the engine. The thermostat can be replaced in a matter of minutes as the housing is located by the distributor cap.
Allow the truck to cool down for an hour. Open the hood to gain access to the thermostat.
Find the upper radiator hose and follow it to the engine. Unscrew the hose clamp at the end of the hose with a flat tip screwdriver. Pull the hose off the thermostat housing.
Unbolt the housing with a socket wrench. Lift the housing cover off to expose the thermostat.
Scrape the surfaces with a razor scraper to clean the gasket material. The removal of the old gasket will help to ensure the housing does not leak in the future.
Pull the old thermostat out of the housing by hand. Insert the new thermostat. The spring end of the thermostat needs to go in first.
Place a new paper gasket around the surface of the housing. Place the housing cover over the housing.
Bolt the housing with a socket wrench. Slide the hose over the inlet pipe. Slide the hose clamp over the hose and the pipe. Tighten the hose clamp with a flat tip screwdriver.
Twist the radiator cap counterclockwise and take it off the radiator. Fill the coolant level with pre-mixed coolant.
Leave the radiator cap off the radiator and start the truck. Allow the truck to warm up. The coolant level in the radiator will drop. Fill the radiator with additional coolant until it is full. Close the cap on to the radiator. Turn the truck off.
