The coolant temperature sensor has a solid brass temperature sensing tip. The coolant sensor supplied is an industry standard component and some engines may already have provision for this type of sensor. The coolant temperature sensor is designed to screw into a threaded hole and protrude into the engine coolant stream. For air-cooled engines, the sensor can be embedded directly into the engine block or used to sense oil temperature. Locate a suitable position on the engine which gives access to the coolant stream before you drill and tap the thread. The sensor should be mounted before the thermostat in the coolant circuit. Since most engines have existing temperature sensor holes, it is often possible to mount the Haltech sensor in one of these holes. If necessary, drain the coolant from the vehicle to fit the temperature sensor then consult the factory manual on how to purge the cooling system of air. Check the engine does not require topping-up with coolant after the engine has reached operating temperature.