4 Symptoms of a Bad Car Thermostat

car thermostat on a wood surface with other parts in the background

A bad car thermostat can be difficult on your wallet because it can ruin the car’s engine if you’re not careful. This is a critical component that, when faulty, must be repaired immediately. Read on to know more about the symptoms or warning signs of a bad car thermostat.

1. Overheating

A bad thermostat can cause the car to swelter, as the thermostat is a heat-sensitive control device situated at the radiator hose. When the engine's temperature reaches its normal operating temperature, this device should open to allow coolant to flow into the engine to regulate the heat. If the thermostat is stuck closed, the antifreeze won’t flow from the radiator, resulting in the car overheating. Thus, if this happens, one of the possible causes is a broken thermostat.

This problem can definitely be attributed to other issues with the cooling system, such as leaking hoses, but checking for a bad thermostat should be on your list as well since this is a fairly cheap, easy fix.

2. Under Heating

If the thermostat is trapped in an open setting, it leads to the engine underheating. The open setting means that coolant will constantly be moving into the engine, whether it is hot enough to need it. Instead of ending up too hot all the time, the engine will have an issue with being too cool.

If you have been driving for a few minutes and your vehicle’s temperature gauge needle is still sitting close to the bottom, it’s time to check your thermostat.

3. Temperature Fluctuations

A malfunctioning thermostat will result in odd temperature fluctuations throughout the operation of the engine. In this case, the thermostat won’t be stuck in any one position, but there will still be false readings causing problems with regulation. The engine temperature will change erratically while the radiator coolant is prohibited from flowing normally.

4. Poor Engine Performance

If the engine’s operating temperature is all over the place while trying to function, engine performance will ultimately suffer. This could lead to reduced gas mileage and, eventually, damage that will cost a bundle to fix.

If you notice any of these issues, don’t hesitate to pop open your hood and check out your car’s thermostat. You can purchase a new thermostat at your local auto parts store, and the repair is an easy one that you can do yourself if you’re looking to save some money.