How do you replace a thermostat on 2003 Honda Accord v6?

To replace the thermostat on a 2003 Honda Accord V6, first, ensure the engine is cool and disconnect the battery. Drain the coolant and remove the upper radiator hose connected to the thermostat housing. Unbolt the thermostat housing, remove the old thermostat, and clean the mating surfaces. Install the new thermostat with the spring side facing the engine, reassemble the housing, reconnect the hose, and refill the coolant before starting the engine to check for leaks.