Guide

Thermostat – What You Should Know?

A thermostat is a part of the cooling system. Its main function is to maintain the optimal temperature of the coolant by directing the coolant to either a small or a large circuit.

The operation of a thermostat is based on the expansion of a wax element, which opens a valve. This directs the coolant to the radiator to lower its temperature. The thermostat opens at a specific temperature, which is predetermined for the given system. When the coolant reaches a certain temperature, the wax filling melts and expands. The increase in the volume of the wax causes the movement of the working piston and opens the radiator circuit (known as the ‘long circuit’) and closes the short circuit. If the temperature falls below the set opening temperature of the thermostat, the wax element hardens.

There are two characteristic failures of the thermostat: failure in the open position and failure in the closed position. The first occurs when the cooling is constantly active, and the fluid flows through the radiator. As a result, the engine cannot reach its operating temperature. This leads to increased fuel consumption and poor cabin heating. The second and more undesirable type of failure is the permanent closure of the thermostat. Because the closed thermostat prevents the coolant from flowing through the radiator and lowering its temperature, this leads to a rapid increase in the temperature of the fluid, which can consequently lead to engine overheating.