The device and principle of operation of the thermostat

What is a thermostat? What is it for? What is the working principle of the thermostat?

Almost all vehicles, the internal combustion engines of which are equipped with forced liquid cooling systems, among their units have a small device called a thermostat. It is located between the power unit of the machine and its radiator..

The main function of the thermostat is:

Ensuring blocking the flow of antifreeze into the radiator of the system until the power plant of the car reaches the optimal heating temperature. After this happens and the engine temperature approaches approximately 90 degrees (depending on the car brand), the thermostat ball valve will open.

In addition to temperature control, the thermostat helps to reduce wear of internal combustion engine parts and reduces the level of harmful exhaust emissions into the atmosphere..

The unit body is made of copper or brass.

The operating principle of the thermostat is simple. Inside it is a small cylinder with a wax ball, which, heating up to a temperature of 82 degrees, begins to expand and melt. The inner pilot pin is connected to the ball and the thermostat valve. Expanding, the wax filler drives the pin, which, in turn, opens the valve. Thus, the antifreeze gets access to the radiator, in which it is cooled. As the car engine begins to cool down, the wax filler also cools down, shrinking and hardening.

The correct operation of the thermostat is very important and its breakdown can easily force you to stop moving in the car..

Overheating of the power unit causes it to «boil», which is fraught with multiple negative consequences for the engine.

According to experts, the most common cause of thermostat failure is corrosion. When the valve is constantly open, the engine of the machine will take much longer, which will have to be spent on warming it up to its optimal operating temperature. And, conversely, with a constantly closed valve, the power unit will very soon overheat, and the movement will have to be stopped before replacing the unit. When servicing the car’s cooling system, it is recommended to change the thermostat every 2 years..

There are various ways to check the thermostat for proper operation..

If it’s removed from your car, you can dip it in a pot of boiling water. Evidence that it is working and the valve has opened will be a characteristic click.

To check the unit without dismantling it from the car, warm up the engine to operating temperature, open the hood, and try with your hand both rubber pipes connected to the radiator, upper and lower. Both should be hot. If it turns out that one of the hoses is cold, it means that due to the inoperative thermostat valve in the system, the circulation of antifreeze is impaired. This unit should be replaced immediately. Fortunately, this procedure is not complicated and not expensive..

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