Thread Size M22 x 1.5. 1x M22 Aluminium Crush Washer 518-0D1-F40. Switching Temp ON 95, OFF 86°c ON 203, OFF 187°F. For example; if the switch temp is too low then the radiator fan will be running unnecessarily and placing unwanted extra load on the electrical system, too high and you may unintentionally be allowing the engine temperature to increase beyond its designed thermal window.