How To Troubleshoot Faulty Thermostat In Your Car

As you perform regular maintenance for your car, a point will come, and you will need to know what a thermostat is and its role in your vehicle. But the most important thing is knowing that a thermostat can stick close or open. Your engine requires coolant to operate smoothly, and the thermostat regulates the coolant flowing to the engine. When you ignite your car in the morning, the thermostat remains closed as it waits for the coolant to attain a specific temperature. Generally, the thermostat’s opening and closing regulate your engine’s temperature. Here is how to troubleshoot faulty thermostat in your car.

How To Troubleshoot Faulty Thermostat In Your Car

Occasionally, your thermostat might fail to open or close at the right time. It is not difficult to troubleshoot thermostat issues. Here is how to approach the issue.

Check Your Temperature Gauge

If you see your temperature gauge hitting the red position within fifteen minutes of driving, your thermostat might be faulty. Generally, your thermostat should not take a lot of time to open. As soon as you start your car, it takes less time for the adequate temperature to build up to facilitate the thermostat’s opening. But if you see the temperature gauge hitting the red part in the first 15 minutes, it is evidence that your thermostat is not opening. 

Check the Condition of The Radiator Hoses

If you realize your engine is heating up, the first thing to check is the radiator hoses. Confirm if any of them is leaking and if there is no leakage, assess the temperature of the hoses. If some are warm and others are cold, then conclude that your thermostat is not opening.

How To Verify The Status & Troubleshoot Faulty Thermostat

If your car exhibits any of the above signs, the thermostat housing might leak due to pressure at the thermostat. To verify the status of your thermostat, you need needle nose pliers and water. Perform the following steps.

Step 1. You have to remove the thermostat from its housing.

Step 2. Take your thermostat to the kitchen as you boil some water on the stove. As the water is heating, ensure its temperature does not exceed the temperature calibrated on the thermostat. To determine this, you must have a thermometer.

Step 3. After the water has attained the required temperature,  hold your thermostat with the needlenose pliers and deep it in hot water. The thermostat should be able to open when the water reaches a specific temperature. 

It would help if you were very keen when doing this because sometimes the thermostat might be attempting to open and close. If such happens, your thermostat is faulty, and you should replace it as soon as possible. 


As your engine is operating, several factors make it heat up. The combustion in the cylinders produces heat as well as friction. Engine coolant performs the role of containing the temperature of your engine. The thermostat performs the function of regulating the flow of coolant in the engine. If it is faulty, there are high chances of your engine not receiving coolant, leading to engine overheating. 

Your thermostat can be faulty, and this guide has elaborated on determining whether your thermostat is defective and how to troubleshoot it.

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