1. Park the vehicle on a level surface, turn off the engine, and allow it to cool down.
2. Open the hood of the vehicle.
3. Look for the radiator cap. It is usually labeled with the word "Radiator" and has a warning symbol about hot liquid.
4. Follow the upper radiator hose from the radiator cap. The thermostat housing is located at the end of the upper radiator hose, where it connects to the engine.
5. The thermostat is located inside the thermostat housing. This may have two bolts (4.0L V6 and 5.0L V8), be held in place by two or three 11mm nuts (5.0L V8s before mid- 2004; this housing does not have a "neck"), be held in place by four 10mm or 11mm bolts (4.0L V6, all 5.0L V8s after about September 2004 (mid-year)). Remove bolts or nuts and discard the old gasket. It sits between the housing flange(s) and the engine's intake manifold at both sides of the head, sealing the upper cooling ports.
