Coolant flow controlling method and apparatus

A method and apparatus for automatically adjusting the flow rate of engine coolant through a heater core in an automobile by automatically determining a temperature difference between the temperature of coolant at a first flow rate before it enters a heater core and a temperature of air exiting the heater core and automatically increasing the flow rate of the coolant to a second flow rate higher than the first flow rate if the temperature difference is greater than a first predetermined temperature difference.