Coolant Sensor

What is an Engine Coolant Sensor?

Your engine uses a  coolant temperature sensor to monitor the temperature of the engine's coolant. This coolant sensor is a vital part of the engine management system. This coolant sensor is used to monitor the temperature of engine coolant temperature by measuring the electrical resistance of the engine's coolant.

 What Does the Coolant Temperature Sensor Do?

The Coolant Temperature Sensor is a small-sized sensor that screws into your engine block in a location that connects directly to a coolant passageway. This sensor is a vital part of your engine's proper operation and is used to ensure your engine doesn’t overheat. Its important job is to measure the temperature of your engine coolant and then send those results to the ECU or engine computer system. The coolant sensor may also be used to regulate the operation of the cooling fan when engine temperatures are too hot. If your engine is operating with a faulty coolant sensor you are more prone to damage caused by engine overheating. KLM Performance strongly recommends the replacement of a faulty coolant sensor as a means to avoid expensive repairs.

When the Coolant Sensor data is transmitted to the ECU this information calculates the temperature of the engine from the Coolant Sensor, the ECU uses mathematical data to change the fuel injection or ignition timing. A cold engine requires different timing of fuel intake than a warm engine.

 With all of these tasks happening several times a minute, it’s no wonder this little coolant sensor often needs replacing. Many times the coolant sensor will get corroded or will leak coolant through the wiring connector. These are common problems we see in the cars that come into our shop. Though, as the driver, it can be very hard to spot the signs of a bad coolant temperature sensor.

Common Warning Signs of a Bad Coolant Sensor

Check Engine Light: The most common sign, as with most engine problems, is the check engine light on your dashboard will turn on. Depending on the type of vehicle, you may be able to read the check engine code to see if it is an engine coolant issue.

A decrease in engine performance or MPG: Have you noticed that your fuel economy has been dropping? This could be due to a bad coolant sensor assigning too much fuel intake which uses up more fuel If you notice that you are driving the same amount of miles as usual but taking more trips to fuel up you may need to have your coolant sensor checked. The cost of repairing the sensor could save you more money than the additional trips to fill your gas tank.

Trouble Starting or Black Exhaust In extreme cases, your car may have trouble starting after the engine has warmed up. You may also notice black smoke coming out of your exhaust. This means that you should get your car serviced as soon as you can before it causes more damage to your engine.

Overheating or Higher than Normal Operating Temperatures: The coolant sensor measures the temperature of your engine’s coolant. If you have a bad sensor, it can often misread the correct temperature which can lead to your engine overheating. Keep an eye on the coolant temperature gauge on your dashboard to make sure you are not experiencing any overheating. See what else could cause your engine to overheat.