Coolant Temp Sensor with O-ring

This OEM coolant temp sensor is used on our Super Swap Package for E46. It sends coolant temperature to the ECU which controls the thermostat and electric fan. A bad sensor will give the ECU incorrect data which can affect the cooling system performance and not activate the backup auxiliary fan, which could lead to overheating. This is also a common source of coolant leaks on late-model BMWs, especially if the hose was replaced but the sensor was re-used. We always recommend replacing the sensor with the hose. New o-ring included.