How do you change the thermostat on your Mercedes ml 270 cdi?

To change the thermostat on a Mercedes ML 270 CDI, 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, replace the old thermostat with a new one, and make sure to use a new gasket. Reassemble everything, refill the coolant, and check for leaks.