Keeping the temperature of your engine coolant low is an essential part of keeping your engine running. But how can you tell if it’s getting too hot?
This is where your engine’s coolant temperature sensor (CTS) comes in.
In this guide we will explore what a CTS is, how it works, and where you can find it.
What is an engine coolant temperature sensor?
An engine coolant temperature sensor measures the temperature of your engine coolant, in order to tell the engine fuel unit (ECU) when to adjust the fuel injection and ignition timing.
The coolant temperature sensor works within your vehicle’s ECU, by sending regulated voltage to the sensor. The resistance to the sent voltage varies depending on the temperature of the engine coolant—this is how the ECU monitors temperature.
The ECU uses the resistance reading to calculate the temperature of the engine coolant and adjusts ignition timing, fuel mix and the cooling fan, to help maintain a regular temperature.
This maintenance is key to keeping your vehicle safe and coolant system performing at its best.
Where can you find the coolant temperature sensor?
It all depends on your vehicle manufacturer. It is usually located near the thermostat of the cooling system or, in certain cases, even within it.
Not all engines have the same sensors. One sends information from the engine to its control unit and the other from the control to the dash. Although this is rare these days, two-sensor cars are still possible.
How to spot a faulty temperature sensor and what it means
Problems can sneak up on you, especially if they are in your cooling system. Here are some key indicators and methods that you can use to detect a problem with your coolant temperature sensor.
An overheating engine
A failing engine coolant temperature sensor can give mixed messages. It can often send a permanent cold signal, but may also send a hot signal when the engine temperature is safe. If this happens, your car might tell you your engine is heating up when it isn’t. Or, as a worst case scenario, not inform you that your vehicle is overheating.
Black exhaust smoke
Your vehicle’s coolant temperature sensor controls the fuel ratio. If there is too much fuel, it might not burn off in your combustion chamber.
If this happens, you will likely notice black smoke from your exhaust. This is because the fuel that was left behind is now being burned there. Although it won’t make your car undriveable, a small amount of black smoke can indicate that your cooling system needs to be repaired.
Bad fuel economy
The coolant temperature sensor is responsible for accurately reporting your car’s coolant temperature. It also ensures that the right mixture of fuel is being used. The cooler the engine’s temperature is, the more fuel is required. If your ECT reports a low temperature but your engine is actually hot or warm, it will likely report a lower temperature.
Fluctuating temperature readings
The engine coolant temperature sensor could be faulty if you notice fluctuations in your engine temperature, or it appears higher or lower than normal while driving. If your engine is not heating up as it normally does, you should get a mechanic to inspect your cooling system. It is possible that your engine is not heating up as it should, even though it may be colder outside.
Faulty engine light
If your coolant temperature sensor has failed or is failing, your ‘check engine light’ may also be on. The check engine light may be activated if your car’s computer detects an issue with the signal it is sending.
Keep your cooling system running as it should do
If you suspect your engine cooling system is carrying a leak, prevent further damage to other areas of your vehicle by using K-Seal. For serious repairs use K-Seal Ultimate and for larger vehicles K-Seal HD.