Serious problems with thermostat can lead to engine brokenness

The thermostat in your car is a small technical unit of great importance. Completely independent, it ensures the operation of the engine in any temperature conditions, preventing overheating of the motor.  The thermostat has a fairly simple structure, and it does not require any additional care or maintenance. However, signs of a bad thermostat in a car should be known well to prevent critical engine failures.

How does it work? The purpose of the thermostat is to control the temperature of the liquid in the cooling system. While the system is warmed up, the thermostat lets the antifreeze (or part of it) go through the radiator, and in a situation when the system is cold, the thermostat pulls the liquid in a small circle.

At what temperature of the engine does the mechanism start? Depending on the type of engine, the range of optimal temperatures of its operation varies, on average between 70 and 97 °C. Thus, when the engine temperature is below the minimum, the resistance of the pistons increases. The thermostat warms-up the antifreeze by running it in a small circle. With sufficient heating of the engine, the run of the liquid begins due to the open valve, while access to the small circle (through the bypass channel) can be completely stopped. This occurs when intensive cooling is required. Under normal conditions, the antifreeze runs in two directions. Hoverer, this rise a question will a bad thermostat cause a car to overheat? Yes, it definitely will. 

Thus, each thermostat has its own temperature index at which the antifreeze pass valve to the radiator is opened – which is indicated on its metal housing and depends on the technical characteristics of the engine. For example, such temperature indicators can be 76°C and even 107°C (for regions with predominantly negative air temperature and harsh climatic conditions).

Symptoms of a bad thermostat in a car

Less problem – is a positive trait of the device simplicity. Consequently, the thermostat can jam in the closed or open state, less likely to break is not timely opening of the valve.

1) Fully closed thermostat leads to overheating of the motor

In this case, it is better to evacuate your car immediately to the service station. In case of overheating, the engine can jam, and smoke. And this will lead to even more issues.

2) Fully (partially) open thermostat leads to piston wear

The engine will warm up more (at low temperatures and can’t warm up at all), the engine oil will be more viscous and worse at lubricating the parts, therefore the resistance to the movement of the pistons will be increased. This one more hint on how to tell if the thermostat is bad in car.

3) The gasket in the thermostat is worn out and caused coolant leaking

In this case, the thermostat itself is working properly, but coolant may be leaking through the gasket. If the initial inspection of the thermostat does not reveal any damage, you should check other systems.

4) Partially open thermostat leads to erratic temperature changes

This indicator may not be immediately noticeable, as modern cars record temperature readings in real time, so just pay attention to them when it seems that the engine is not running stably. You can also use inCarDoc, but we'll tell you more about that later.

Secondary signs of a bad thermostat in a car are strange sounds of the engine and heater problems. Engine rumbling and knocking can occur for various reasons. We wrote an interesting article about this. However, you can start looking for the problem with the thermostat. As to heating issue. Drivers are likely to discover a problem with the thermostat in the fall and winter when they turn on the interior heating. In this case, no matter how high the temperature is set, the outside air will remain barely warm.

How to replace a bad thermostat?

So, once you understand what happens when a thermostat goes bad in a car, the next question is how to replace the faulty component. This is a fairly simple process. The thermostat is located at the top of the engine near the radiator hose. Of course, the engine must be cold before replacing it. Remove the radiator hose, but be prepared for any residual fluid to drain out of it. Remove the thermostat bolts and remove the thermostat. Replace the gasket and clean the surface. Install the new gasket and thermostat, and put everything back in place. Change the coolant. Run the engine to make sure you have done everything correctly.

How to avoid problems with the thermostat in the future

 Failure of the thermostat is not a common problem, and any issues with this unit can be avoided:

1. If the thermostat itself is made of high quality. If you have to replace a thermostat, buy a high-quality model. This is not a component that should be skimped on.
2. It is necessary at least once a year (better after winter) to diagnose the service shop.
3. Thermostat does not fit your engine type. This brings us back to the first point. Be careful when choosing a thermostat.

Do not forget to monitor your car and regularly check the operation of electronic systems using inCarDoc. Symptoms of a bad thermostat in a car can be identified earlier in the process of recording the actual engine parameters. The inCarDoc app offers this functionality with the use of graphs and customization of parameters in the paid version. But even in the free version of the app, drivers can view engine temperature readings while travelling. You can also conduct DTC diagnostics and reset trouble error (P0128) that indicate a malfunction of the thermostat. If the error returns again, physically check the thermostat for damage or contact a service center to identify the problem.