Evaporation cooling system for a liquid-cooled internal-combustion engine

An evaporation cooling system for a liquid-cooled internal-combustion engine having a coolant jacket filled completely with coolant, comprising a condenser, a forward flow line operatively connected with the condenser, a vapor separator arranged at a high point in the forward-flow line to the condenser, a condensate pump arranged in a return flow line from the condenser to the cooling jacket and having a connecting line extending from the vapor separator in parallel with the condenser to the return flow line, and an expansion tank connected to the vapor space of the condenser, wherein the expansion tank, is when the coolant is cold, connected with the atmosphere and is, at an operating temperature to the coolant, disconnected from the atmosphere,

• a temperature-controlled vent valve is operatively arranged in the expansion tank, and
• a molecular sieve is arranged, as viewed in a flow direction, downstream of the vent valve.