Abstract: A coolant temperature control system for an internal-combustion engine in a motor vehicle having an electrically heatable thermostatic valve whose method of operation can be shifted by electrical heating in the radiator operation direction. Control devices are provided for recognizing a defect of another system in the motor vehicle which controls the coolant flow. When a defect of this other system is recognized, the thermostatic valve is heated. Particularly when a defect is recognized, the heating of the thermostatic valve is controlled such that the coolant temperature is maintained below a preset coolant temperature threshold. Preferably, the recognition of a defect is carried out by means logically monitoring output signals of the other system.

Abstract: A cooling device is provided for a motor vehicle liquid-cooled internal combustion engine with a radiator connected to the supply and return lines of the engine. The radiator has a filling opening closable by a cap. A temperature-controlled thermostatic valve, via which the coolant is sent completely or partially either through the radiator or through a bypass between the supply and return lines to bypass the radiator, is controllable by electrical heating. An electrical switch is mounted on the filling opening such that upon actuation the thermostatic valve is electrically heated, so that the coolant passes at least partially through the radiator.