The coolant or water temperature sensor 2874A018 is used to measure the temperature of the engine coolant, which can then be fed back to the ECU, to adjust the timing and fuel ignition. Helping to ensure less fuel is supplied when the engine is warm or more when the engine is cold. Alternatively, some engines may use this to provide a reading for a dashboard readout or as an indicator to switch on an electric fan. Temperature plays a vital role in engine performance calculations; a sensor failure can quickly lead to issues such as: black smoke, poor fuel economy, and overheating. Perkins temperature sensors are carefully selected to they are reliable and durable to give your engine long, productive life.