The thermostat is a small part in the mechanism of an internal combustion engine, which is responsible for the operation of the cooling system. When this component stops working under the hood of the vehicle, thick accumulations of steam begin to come out, a similar picture can often be seen in various films and series.
The thermostat performs the automatic transmission of chilled fluid flows with different temperatures through the cooling system. It works in a large circle when the engine overheats - passing through a radiator, and in a small circle when the engine is cold - bypassing it. If this part does not work correctly, then in the cold season the stove freezes and it is impossible to warm up the car interior. There is a thermostat both in a used car and in a new one if they use a closed version of a liquid cooling system with forced circulation of a liquid with a low temperature. The principle of operation of the part is identical for all vehicles, regardless of the country of manufacture.
Thermostat working principle
Its main component is a mechanical valve, which begins to work under the influence of a clear mechanism. A special heat-sensitive wax is placed in the hermetically sealed case of the device, which, under the influence of high temperatures, begins to melt and grow in volume, thereby squeezing the rubber chamber. In turn, the camera begins to push out a metal chromed rod that drives the valves.
When the engine starts, the thermostat is closed so that the antifreeze cannot get into the radiator and cool. During this period of time, it moves along a small circle of the cooling system and cools the heating engine. When the temperature of the liquid reaches 90 ° C, the engine accelerates to the desired mode; if it is above 90 ° C, it will start to overheat, so the antifreeze needs to get rid of the heat and it goes into a big circle.
This principle of operation is very simple, but when the integrity of the structure is not respected, wax can leak due to the use of low-quality antifreeze (antifreeze) or corrosive processes, which will lead to an increase in the friction force of the movable rod.
Key indicators of poor thermostat performance:
1. The valve seals when closed. In a similar situation, the sensor is triggered, but cannot open the shutter, due to which the antifreeze continues to heat up. You get information about this on the dashboard when the overheat indicator lights up.
2. The valve is not tightly closed at the beginning of work. The fluid moves immediately in a large circle and cannot reach the temperature necessary for the engine to work at 90 ° C.
Common symptoms include:
1. Prolonged warming up of the car engine to the desired mark or its overheating.
2. The arrow, which is responsible for the temperature of the engine, drops sharply when the car picks up speed and rises when it stops.
3. The lower branch pipe becomes warm in a couple of minutes of warming up - means that the thermostat is constantly open.
4. The thermostat is stuck and is in a closed state when the engine itself begins to boil, and the lower pipe continues to remain cold when the engine is warm.
How to check the thermostat without removing it from the machine
Check the operation of the device, without removing it can only conditionally. An exception can only be cases when it is stuck. In such a situation, the conclusion about the health of the thermostat can be made by checking the temperature of the pipes, the period for which the heating was performed and the temperature sensor.
To check, turn on the engine and wait 2 minutes, then touch the hose going from the thermostat to the radiator. During this time, the valve still does not work and the hose should be cold. If it is hot - there is any malfunction in the valve, and when after some time the hose does not become hot - the valve is stuck and the device should be repaired.
Professionally check the thermostat ways only specialists. If there are complaints about the engine, it would be better to contact experienced workers and fix the problem in a timely manner.