Abstract: A cooling circuit (5) for an internal combustion engine in which a throttle (2) is provided upstream of a heat exchanger (10, 11). The throttle (2) equalizes the oil pressure in the internal combustion engine in front of the heat exchangers and insures that this occurs almost independently of the temperature of the oil. By this provision, the heat exchangers can be fabricated with the least expense since the danger of bursting is reduced.

Abstract: A cooling system for water-cooled internal combustion engines, particularly boat motors comprises a pump for circulating cooling water over a heat exchanger and through an expansion vessel, a raw water pump for maintaining a flow of raw water as a cooling fluid through the heat exchanger, a reservoir, and a pressure relief valve and a check valve which are connected in parallel between the expansion vessel and the reservoir. In order to reliably maintain a high pressure in the expansion vessel and to maintain an emergency operation in case of a leak in the cooling system and to accomplish this with simple means, the reservoir is pressure-tight, the line which connects the expansion vessel to the reservoir opens into the uppermost portion of the reservoir, and the raw water pump is connected by a discharge line to the lowermost portion of the reservoir.