How do you replace the thermostat on a 1993 Mazda rx-7?

To replace the thermostat on a 1993 Mazda RX-7, first, ensure the engine is cool and disconnect the negative battery terminal. Drain the coolant from the radiator and remove the upper radiator hose connected to the thermostat housing. Unbolt the thermostat housing to access the thermostat, replace it with the new one while ensuring the rubber O-ring is in place, and then reassemble everything by reversing the disassembly process. Finally, refill the coolant and check for leaks before starting the engine.