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Your Radiator thermostat worn out? » Read more about common malfunctions • Repair • Replacement manual
Cooling under control with the thermostat
The thermostat is a small component automatically regulating the cooling system. A functional thermostat keeps the engine temperature at constant level. A failing thermostat causes rapid engine wear.
Construction of a thermostat
he thermostat is a valve, separating the two cooling circuits in an engine, only opening when necessary. This small metal valve reacts to the coolant temperature with help of a spiral coil and a wax core. When the environmental temperature rises too high, the thermostat lets coolant flow through. The wax within melts and the spiral coil opens a valve. Dropping of temperature causes the coolant thermostat to close and the wax to solidify.
Position of the thermostat
The thermostat sits close to the engine and is easy to find. Where large and small cooling circuit merge, a Y-shaped node of three hoses is found. This node is generally a cast aluminium component which can be opened. The thermostat is located exactly in the centre. In many cars, the thermostat is situated right on the engine. There too, its position can be found by the thick coolant hoses.
Task of the small and the large cooling circuit
Metals shrink when they are cold and expand when heated. An engine is built in such a way that components exactly fit together at operating temperature. Exceeding that temperature causes engine wear. If the engine permanently runs too cold, the components do not adequately slide, but rattle and bounce instead, also increasing wear. In order to bring the engine at its operating temperature as quickly as possible the coolant is pumped through the engine again after its circulation. It keeps on circulating as the engine gradually heats up to a point where it almost gets too hot. At that moment the thermostat opens and the large cooling circuit lets the radiator cool the engine. If the cooling function of the radiator is no longer sufficient, the fan switches on and additionally cools the coolant. In the meantime the thermostat keeps the large cooling circuit open.
Damage to the thermostat
A thermostat can gradually lose its function. If it has been in service for too long a period, it can even break. Generally, a defective thermostat prevents the engine from heating up adequately. This becomes apparent by switching on the interior heating. If it only produces tepid air, a defective thermostat could be the cause. Replacing a thermostat is not very difficult. It is always found where three thick coolant hoses come together in a housing. This housing is screwed tight with a few metal screws. Loosen them and the old thermostat can be pulled out with pointed pliers. Some coolant might get lost in the process. Be certain to replenish it.
Branded quality thermostats
A thermostat is a small, cheap but very important component. For reliable control of the cooling circuit, precision and durability are essential. Cheap thermostats from unknown manufacturers do not offer these conditions. Thermostats from branded companies supply tested and guaranteed quality. The temperature in an engine is accurately regulated by operating and high-grade thermostat, ensuring maximal fuel efficiency and comfort.
