The Ford Ranger is a small pickup truck available with three different engine configurations. The Ranger has not been majorly redesigned since 1994, so most repair instructions for 1994 and newer vehicles will be basically the same. Learn to change the thermostat in your Ford Ranger, regardless which engine it has.
Park your Ranger on level ground in an area free of distractions. Disconnect your negative battery cable and let the engine cool off for at least 30 minutes.
Remove the engine brush guard from underneath the engine bay (if equipped) to access the radiator drain plug. Remove the drain plug and let the engine coolant completely drain into the pain. Keep the coolant away from children and animals. It is highly toxic.
Remove the wiring harness from the rear of the thermostat (located behind the radiator). Use the socket wrench to remove the thermostat and its gasket. Wipe the are clean with a rag and discard the old gasket.
Mount the new thermostat and gasket to the radiator with the torque wrench. The proper torque level for the Ford Ranger is 89 inch-pounds for four-cylinders and 4.0 L V6 engines. The proper level for the 3.0 L V6 engine is between 15 and 22 foot-pounds.
Replace the drain plug, wiring harness and engine coolant. Reconnect the negative battery cable and start the engine to check for leaks. If there are no leaks, replace the engine brush guard.