How do you replace thermostat on Toyota solara?

To replace the thermostat on a Toyota Solara, first, ensure the engine is cool, then disconnect the negative battery terminal. Drain the coolant from the radiator, remove the upper radiator hose, and unbolt the thermostat housing. Take out the old thermostat, clean the mating surfaces, install the new thermostat with the correct orientation, reassemble the housing and hose, refill the coolant, and reconnect the battery. Always check for leaks after starting the engine.