Cooling system with water guided in the circuit as the heat transport medium, comprising an application device flowed through by the water and functioning to apply heat to the water, a heat exchanger flowed through by the water and functioning to discharge heat to the surrounding air, and a water container, which is arranged in the flow direction between the heat exchanger and the application device in a tube arrangement, which connects the heat exchanger, the application device, and the water container with one another and has at least one circulating pump, characterized by the following features: - the heat exchanger comprises an inlet connected to an inlet manifold and an outlet connected to an outlet manifold on its one, first end region and a deflection manifold on its other, opposite second end region; - the inlet manifold and the outlet manifold are arranged in a V shape with respect to each other; - the deflection manifold comprises a first branch and a second branch, which are arranged in a V shape with respect to each other, and a connecting branch connecting the first branch and the second branch to each other at their respective upper ends; - a first tube arrangement which can be flowed through, extends between the inlet manifold and the first branch of the deflection manifold, and rises in the flow direction from the first end region in the direction of the second end region of the heat exchanger, and a second tube arrangement which can be flowed through, extends between the second branch of the deflection manifold and the outlet manifold, and descends in the flow direction from the second end region in the direction of the first end region of the heat exchanger, wherein the connecting branch of the deflection manifold can be flowed through by the entire amount of water flowing through the first tube arrangement; - the water container is unpressurized; - an open ventilation line, which can be flowed through from the deflection manifold to the water container in a cooling operation, extends between the water container and the connecting branch of the deflection manifold. - the heat exchanger comprises an inlet connected to an inlet manifold and an outlet connected to an outlet manifold on its one, first end region and a deflection manifold on its other, opposite second end region; - the inlet manifold and the outlet manifold are arranged in a V shape with respect to each other; - the deflection manifold comprises a first branch and a second branch, which are arranged in a V shape with respect to each other, and a connecting branch connecting the first branch and the second branch to each other at their respective upper ends; - a first tube arrangement which can be flowed through, extends between the inlet manifold and the first branch of the deflection manifold, and rises in the flow direction from the first end region in the direction of the second end region of the heat exchanger, and a second tube arrangement which can be flowed through, extends between the second branch of the deflection manifold and the outlet manifold, and descends in the flow direction from the second end region in the direction of the first end region of the heat exchanger, wherein the connecting branch of the deflection manifold can be flowed through by the entire amount of water flowing through the first tube arrangement; - the water container is unpressurized; - an open ventilation line, which can be flowed through from the deflection manifold to the water container in a cooling operation, extends between the water container and the connecting branch of the deflection manifold.