Provided is an engine cooling system including: a first coolant circulation channel passing through an engine; a second coolant circulation channel bypassing the engine; an electric water pump (EWP); a connection channel connecting the first coolant circulation channel and the second coolant circulation channel; an electromagnetic valve arranged in the connection channel to change a flow rate of a coolant passing through the engine and flowing from the first coolant circulation channel to the second coolant circulation channel; an EGR cooler, a heater core, and an exhaust heat collection device arranged in the second coolant circulation channel; and a control unit, wherein closing of the electromagnetic valve is prohibited if there is an actuation request of the EGR cooler, the heater core, and the exhaust heat collection device when there is a valve closing request of the electromagnetic valve.