This manifold temperature sensor monitors coolant temperature at the water manifold and sends a signal to the engine control unit for fuel delivery and cooling fan regulation. It is installed directly into the manifold, where the probe tip contacts the coolant flow. A failed sensor can cause incorrect temperature readings, leading to poor cold-start behavior, over-fueling, or the cooling fan running continuously. VDO manufactures this sensor to match the original thread form and sealing geometry of the housing, ensuring a leak-free seal without additional adapters. When replacing, clean the manifold port and install the sensor with a new sealing washer.