COOLING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

A cooling system for an internal combustion engine is a cooling system for an internal combustion engine mounted on a vehicle. It is equipped with an air conditioner which is mounted on the vehicle and has a heat exchanger, a first passage which is connected to the heat exchanger and supplies cooling water of the internal combustion engine to the heat exchanger, a second passage which is connected to a cooling apparatus for oil which fills a speed change mechanism connected to the internal combustion engine or for oil which fills the internal combustion engine and which supplies the cooling water to the cooling apparatus, a flow control valve which is configured to control the flow rate of the cooling water to the first passage and the second passage, and a controller which is configured to control the internal combustion engine and the flow control valve. When the temperature of the oil is higher than the temperature of the cooling water, the controller performs first control which controls the flow control valve to a position in which the first passage and the second passage are open.