How do you replace the thermostat in a 2004 ford sport trac?

To replace the thermostat in a 2004 Ford Sport Trac, start by ensuring the engine is cool and disconnect the negative battery cable. Drain the coolant from the radiator, then remove the upper radiator hose from the thermostat housing. Take off the thermostat housing bolts, lift off the housing, and replace the old thermostat with a new one, ensuring the gasket is in place. Reassemble the housing, reconnect the hose, refill the coolant, and reconnect the battery.