Information - Thermostat (radiator thermostat)

The thermostat is needed in order to regulate the amount of coolant that passes through the radiator. This ensures an optimal temperature mode for the whole system. This item is located in a hose between the radiator and the cooling jacket of the engine. Cars with powerful engines are provided with thermostat with electric heater, which enables a two-step temperature control of the coolant. In order to ensure that, there are three working positions in the construction of this item. When the engine is submitted to full load, the electric heater ensures a total opening of the thermostat. At the same time, the coolant temperature drops to 90 ° C, and decreases the possibility of engine knock. Usually, the coolant temperature holds within 105 ° C.

The thermostat itself is made of brass. To the bottom of the thermostat housing there is a weld bellows (sylphon) with an auxiliary valve and a hollow shaft with a main valve. Fabricated in the form of a cylindrical sylphon made of thin brass, the thermostat bellows is filled with a mixture of water and ethanol, which gets easily heated and boiled. When the water temperature is below 70 ° C, inside the bellows there is a low pressure of saturated liquid vapors, as it gets compressed under the pressure of the elastic corrugated walls.

Apart from that, the main valve is fully closed, and the auxiliary one - open. Moving in s short circuit, the water bypasses the radiator. Under the pressure of the evaporating liquid and at a water temperature above 70 ° C, the sleeve gets stretched, the spindle and the valves are put forward, which allows the water to enter the radiator through the opened main valve. When the water temperature exceeds 85 ° C, the auxiliary valve closes the side openings and cuts the access of water from the thermostat to the water pump.

If you have detected a problem with your thermostat, you need to check or replace the faulty part in a repair shop or garage. In order to avoid additional expenses for any part, for example radiator, brake hose or expansion valve, order it in our online store, and then replace it. This way you will save precious time and money.

What you need to know about thermostat replacement: lifetime limits, common defects and their signs, tips and recommendations

Averagely, replacement of the cooling radiator thermostat is performed every 4 years of exploitation or after 100 000 operational kilometers.

If the component stops working correctly earlier, it also should be replaced. In most cases the cooling system thermostat breaks down because of valve jamming as a result of soiling, corrosion.

The fact that the antifreeze thermostat needs diagnostics is characterized by engine overheating or, vice versa, its inability to reach the working temperature and keep it. Engine overcooling is characterized by increased fuel consumption and lowering of heater operational efficiency in the passenger compartment. In case of overheating the appropriate indicator on the dashboard activates. You can also notice appearance of smoke from under the bonnet and scent of cooling liquid in the cabin. Similar signs can characterize defects of the oil radiator thermostat if it is included in car construction.

Diagnostics of the cooling liquid thermostat can be performed without its demounting. For this you need to start the cool engine and wait 2 minutes, then check the cooling liquid hose going from the thermostat to the radiator. This time is not sufficient for valve activation, thus the hose must be cold. In case if the pipe of the car thermostat gets warm at once or doesn’t get warm at all after a while, then the component needs replacement.

In order to replace the component you should drain antifreeze into the prepared tank after the engine cools down, remove hoses from pipes of the car thermostat. Then unscrew fixation nuts and remove the cap. Remove the defective component, install a new one, set the cap, apply greasing material to it, tighten fixations and fill cooling liquid. Replacement of the thermostat sealing ring is performed together with the thermostat itself. Sometimes replacement of the thermostat body in assembly is required. Moreover, the replacement procedure sometimes takes demounting of the radiator, fan viscous coupling or other components. That is why it is better to contact a service station for thermostat replacement.

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