Cooling system for a liquid-cooled internal combustion engine, especially for motor vehicles

A cooling system for a liquid-cooled internal combustion engine, especially for motor vehicles, comprises a cooling circuit running to a radiator and a pump by way of the internal combustion engine and a bypass line circumventing the radiator, the passage cross-section of which line can be adjusted by a valve control device as a function of the temperature of the cooling water. According to the temperature of the cooling water, a control unit influences a flow of cooling water flowing through a cooling water circuit of the cylinder head and/or through a cooling water circuit of the crank casing of the internal combustion engine. In order to obtain a cooling system in which the cooling water flowing through the cooling water circuits of the internal combustion engine can be influenced in its rate of flow according to the operating conditions of the internal combustion engine, the cooling water flow in the cooling water circuit of the cylinder head and in the cooling water circuit of the crank casing of the internal combustion engine are controlled separately from one another by a control unit comprising two thermostat valves.