Evaporation cooling system for an internal combustion engine

An evaporation cooling system for an internal combustion engine which is isolated from the atmosphere comprising main condenser means for condensing vaporized coolant, the condenser means being only partly filled with liquid coolant when the engine is cold and being complementarily filled with air, a vapor line extending between cooling chambers in the engine and the main condenser means, separator means in the vapor line between the engine and the main condenser means for separating liquid coolant from vaporized coolant, a condensate line for carrying liquid coolant means from the condenser means to the engine cooling chambers, at least one compensation tank containing an elastically yielding wall to accommodate air displaced by the evaporated coolant from cooling circuit components during vehicle heater operation of the engine, at least one heat exchanger receiving liquid coolant from the condensate line, at least one vent line leading from a cooling system component to the compensation tank, the vapor line between the cooling chambers of the engine and the main condenser means branching off from the cooling chambers at a level ensuring that it carries heated liquid coolant as well as vaporized coolant, and a bypass line for liquid coolant extending between the liquid outlet of the separator and the condensate line to bridge the main condenser means.