How do you change the thermostat on a 2004 Hyundai xg 350?

To change the thermostat on a 2004 Hyundai XG350, first, make sure the engine is cool and disconnect the negative battery cable. Drain the coolant from the radiator, then remove the upper radiator hose and the thermostat housing bolts. Replace the old thermostat with a new one, ensuring the gasket is properly seated, and reassemble by reversing the disassembly steps. Finally, refill the coolant and check for leaks before starting the engine.