EGR cooler system

An EGR cooler system, comprising:

• a water-cooled EGR cooler that is included in an exhaust gas recirculation system which sends part of exhaust gas from an exhaust passage of an internal combustion engine back to an intake passage of the internal combustion engine, and that cools the exhaust gas to be sent back to the intake passage;
• an EGR cooler cooling device capable of cooling coolant to be supplied to a heated portion of the internal combustion engine and coolant to be supplied to the water-cooled EGR cooler;
• a coolant path which is separate from a path provided with an engine cooling system, wherein the coolant path connects the EGR cooler and the EGR cooler cooling device;
• a water pump that circulates the coolant within the coolant path such that coolant cooled by the EGR cooler cooling device reaches the EGR cooler without cooling the internal combustion engine;
• a bypass passage through which the coolant in the coolant path may bypass the EGR cooler cooling device or the water-cooled EGR cooler;
• and
• a flow control valve that regulates an amount of coolant flowing into the bypass passage based on a temperature of the coolant flowing through the coolant path.