Today we will give you complete information about the symptoms of bad thermostat, it is a part used in the engine of the car, due to which there are many problems.

Thermostat is a type of valve which is fitted in the water elbow and works to stop and start the circulation of water.

The engine needs a thermostat valve for regular cooling and heating, but many mechanics remove it and direct the water elbow.

After that the problem that arises in the car can bother you a lot, so today we will tell you about the signs of a bad thermostat in car.

what is thermostat valve in petrol and diesel engine

The thermostat valve is installed in the water elbow in the engine and it prevents the car from overheating, which keeps the engine temperature normal.

When the thermostat valve is installed in the engine of the car, at that time when we start our car, after starting the car, until the temperature of the engine reaches 90 degrees, the thermostat valve does not open.

And as soon as the engine temperature exceeds 90 degrees, the thermostat valve opens. There is a temperature switch near the valve, when the thermostat touches the hot coolant temperature when the valve is open.

So this switch prepares a signal and tells the ecm that the engine temperature has increased, the ecm turns on the radiator fan to cool the engine, which keeps the engine cool.

top 10 symptoms of bad thermostat in car

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(1) . check engine light is on

The first symptom of a thermostat valve is the check engine light is on. As soon as the thermostat valve is damaged, the yellow color check engine light turns on in the dashboard meter of the car.

This is a warning light, when this light comes on, we are indicated to stop the car, it can be said only after scanning the car whether the car can be driven or not, so stop the car as soon as the check light is on.

(2) . car engine overheat

After the problem in the thermostat valve, the second symptom that will appear is that the car engine will overheat. As soon as you start the car, the engine becomes very hot.

The overheat warning light turns on in the dashboard of your car, it is different from the check engine light, this light means that the temperature of the engine has increased a lot.

And this problem can happen to you again and again, in this case you should get the car checked by the mechanic so that this problem can be fixed.

(3) . coolant leak in bottle

Whenever there is a problem with the thermostat valve in the car, coolant starts leaking, most of which comes out of the coolant bottle or starts leaking from the water elbow.

In some cases, if care is not taken and the car overheats, the coolant starts bursting out of the pipe, which can cause the headgaskit to explode.

(4) . drop mileage

bad thermostat valve can reduce the mileage of your car very much we had a chevrolet ac car which had very low mileage and on scanning the car no fault code was found

Nor was there any other problem in the car, in that car water was used instead of coolant, due to which when we opened the water elbow, we found that the thermostat valve was completely chocked and had dust in it.

The thermostat valve was working because of a small hole, we changed that water elbow and found that the mileage was very good, so use coolant.

(5) . ac cooling reduces

A bad thermostat valve can kill your car’s ac cooling because the engine temperature needs to be right for the ac to function properly.

The thermostat valve installed in the engine keeps the tempreture of the engine from 80 degree to 90 degree which ac works well but when the thermostat valve is removed from the engine or gets damaged

At that time the tempreture of the engine starts getting very high due to which the ac does not do cooling, the ac shuts down again and again and there is no cooling in the cabin.

(6) . car starting problem

Bad thermostat valve causes starting problems in your car because thermostat valve helps in heating and cooling the engine.

And when there is a problem with the thermostat valve, it also changes the tempreture of the engine, which also spoils the fuel mixture and causes problems with starting the car.

(7) . radiator fan runs fast

This can also be a major symptom for your car. Whenever the thermostat valve in a car is damaged or removed, the radiator fan runs very quickly.

Because when the thermostat valve is bad or not there, then the car starts, it does not heat up quickly, but when it is hot, it does not cool down, due to which the ecm turns on the radiator fan after 15 to 20 seconds.

(8) . engine performance is reduced

Its performance is very important for any car, if the thermostat valve gets damaged or dust accumulates in it, then the engine performance decreases.

Because the temperature of the engine keeps increasing due to the thermostat valve, due to which the engine does not work properly and the pickup decreases.

(9) . smell of burning

Whenever the thermostat valve of your car is chocked and the supply of coolant stops due to which the engine heats up a lot.

If you pay attention, then at that time you will get the smell of burning near the engine, you will feel that something is burning, if you feel like this, then you should stop the car.

(10) . coolant pipe will burst again and again

A bad thermostat valve can tear the coolant pipe repeatedly because when the thermostat valve is bad, the engine temperature rises too much.

In that time, all the pipes of the coolant get heated and due to not tolerating the heat for a long time, the pipe bursts and the coolant leaks, if the thermostat valve is not changed, then the pipe bursts again and again.

If there is a problem of thermostat valve in your car, then you can see the above mentioned 10 symptoms in your car.


Hope that you have got complete information about symptoms of bad thermostat in car and now you will not have any problem related to it, if you have any problem related to it, then comment below and tell us your problem, we will help you, our work. you have to provide correct information

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Know the answers to some questions

Q . Why does the thermostat valve go bad?

ans . The thermostat valve gets damaged by using water instead of coolant because water causes rust in it which collects dust.

Q . Can a bad thermostat valve cause engine seizure?

ans. If the thermostat valve goes bad then the engine will overheat and if you keep driving the car then the headgaskit will burst and after that the engine may seize.

Q . When does the thermostat valve open?

ans. When the engine temperature goes above 80 to 90 degrees or more than the rate set by the company, the thermostat valve opens and the radiator fan runs according to the signal from the ecm and the engine cools down.

Q . Where is the thermostat valve located?

ans. The thermostat is fitted inside the water elbow fitted in the valve head.

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