The Mazda Miata is equipped with a single engine-mounted temperature sensor. As its name suggests, the sensor's purpose is to monitor the temperature of the engine and send that information to the temperature gauge inside the car. If the sensor does not work properly and the engine overheats, the driver may be unaware of the problem until the engine is seriously damaged. Fortunately, a replacement sensor is relatively inexpensive and takes only a few moments to install.
Allow the engine to cool completely, then drain the radiator by removing the bolt on the bottom of the radiator with a wrench.
Locate the temperature sensor on the back of the cylinder head. A single wiring harness attaches to the top of the sensor.
Squeeze the two clips on the tip of the sensor's wiring harness together, then pull the harness off of the sensor.
Grasp the knurled base of the sensor with an open-end wrench, then turn the sensor in a counterclockwise direction with the wrench until the sensor detaches from the engine.
Coat the new sensor's O-ring with antifreeze, then slide the O-ring onto the bottom of the sensor.
Hand-tighten the sensor into the engine to ensure that the sensor's threads align with the threads in the engine.
Turn the sensor with the open-end wrench in a clockwise direction only until the sensor is snug. Over-tightening the sensor could break it.
Press the wiring harness onto the top of the temperature sensor until it snaps into place.
Mix a 50/50 ratio of full-strength antifreeze and water, then fill the radiator with the mixture.
