Cooling apparatus for engine

An engine cooling apparatus having a heat storage tank in a cooling circuit and designed for improved efficiency in coolant replacement is provided. The cooling apparatus is an engine cooling apparatus 100 having a heat storage tank 1 that stores and maintains the temperature of cooling liquid let out from the engine into an engine cooling circuit 110. The heat storage tank 1 is mounted in a vehicle so that a housing 20 of the tank is retained to a lower portion of a tank body 10 and so that the housing 20 is positioned at a lowermost end portion of the cooling circuit in a vertical direction. A drain port 27a is provided on an inlet passageway. In this cooling apparatus, a portion (drooped portion 28) of a cooling liquid channel 115 upstream of the drain port 27a is lower than the position of the drain port 27a in the vertical direction.