How do you change the thermostat on a Land Rover discovery?

Usually located in a removable housing at the engine end of the upper radiator hose Drain about 1 gallon of coolant from the radiator Remove this housing Make note how thermostat is installed Clean both surfaces Replace thermostat and gasket Re-install housing Re-fill coolant slowly to prevent an airlock Start engine and look for leaks Run engine to normal operating temperature with heater on Re-check coolant level