be started in a cold state the engine coolant temperature thwe be lower than the cold state criterion temperature thwl and that preheat have been completed the drive period tpm for the electric water pump 15 be equal to or longer than the predetermined period tpmx 3 that the engine e be started in a hot state the engine coolant temperature thwe be equal to or higher than the cold state criterion temperature thwl 4 that the engine e have just been started the fuel injection amount cumulative value fia be smaller than the predetermined cumulative value fix in the preheat mode a the flow rate control valve 22 is fully opened b the open close valve 23 is opened c all the ports of the three way valve 24 are opened and d the electric water pump 15 is driven the engine cooling device 1 is controlled according to these patterns in the coolant circulation stoppage mode a the electric water pump 15 is stopped b the flow rate control valve 22 is fully closed c the open close valve 23 is closed and d all the ports of the three way valve 24 are closed the engine cooling device 1 is controlled according to these patterns in any of the aforementioned respective control modes the thermostat 21 is basically held closed referring now to fig5 and 6.