You didn't specify what kind of car you have, but it sounds like a classic case of a bad engine thermostat. It acts as a shut off valve between the coolant in your engine-heater core, and the coolant in your radiator. They usually fail in the open position, this will cause coolant to circulate thru the entire cooling system instead of the closed loop of the engine-heater core. A quick fix is to place a piece of cardboard in front of your radiator so air can't flow through it as you drive. Watch your temperature gauge to see if it rises as you drive. Be careful to not overheat the engine though! A thermostat is relatively cheap to buy, and can be simple to replace-dependent upon the vehicle. A mechanic is in order if you are not the handy type, but if you are good at fixing things, it should pose no problem.. A word of advice, a check of all components of the cooling system should be done- belts, hoses, and radiator condition to ensure you don't have more than one problem. New coolant should be installed if it is more than 3 years old, so that usually means a coolant flush should be done as well. Good luck!
