Vehicle Repairs. We've Got What It Takes. A combustion engine must operate within a certain temperature window in order to function optimally. The temperature is controlled by a coolant and a thermostat. The thermostat ensures that the engine reaches its ideal operating temperature as quickly as possible and then maintains it continuously. A defective or blocked thermostat can cause the engine to overheat. This is why febi only offers coolant thermostats in OE matching quality. Quality by Conviction. Our quality management tests the offered thermostats for different requirements and loads. These include function, accuracy of fit, dimensional accuracy, and material quality. Supplied Complete. Repaired Non-stop. In everyday workshop life, it is not uncommon for a worn part to have to be replaced as well as any fixings. However, these additional parts - usually bolts or nuts - are often not included with the individually available replacement part. febi mainly offers thermostats with housings in which the seal and the temperature sensor are already integrated.