This temperature sensor monitors coolant temperature in the engine cooling circuit. It sends a signal to the instrument cluster or engine control unit so the operator can see the operating temperature and the system can adjust fuel delivery or trigger a warning if the engine overheats. The sensor threads into the cylinder head or thermostat housing using a standard thread; the single blade terminal connects to the wiring harness with a push-on connector. A failed sensor may cause an incorrect temperature reading, a persistent cold-start enrichment, or a no-start condition if the ECU relies on the signal for injection timing. When replacing, clean the sealing surface and tighten the sensor to the specified torque to prevent coolant leakage.