Nissan Repair: smell from air conditioner, coolant leaks, radiator coolant

Question
I have a 2011 Nissan Cube with 6000 miles that I recently purchased. It was an executive car owned by someone in Georgia. I am smelling a strong sweet smell coming from the air conditioning that is causing some allergic reaction with my wife.
I understand there can be problems with mold and mildew in the air condenser(?)if water collects.  Would it be unusual for a car of this age to have this problem?  Is there a remedy that would not involve using chemicals that may cause other odors in the car?
thanks, Tom

Answer
The smell you've described is the unmistakable smell of hot radiator coolant/antifreeze. I suspect there is a coolant leak either in the heater core or in one of the hoses. When the a/c blower runs, picks that smell through the vents and blows it in the interior of the car. Even though the a/c and the heater are 2 different things, the a/c compressor will run when the climate control is set on "auto" to maintain the preset temperature. The a/c condenser is mounted in front of the radiator and the a/c evaporator is mounted inside the car. There is no way that mold or mildew can be found in these closed systems. However, if the evaporator drain tube drains inside the vehicle instead of the outside it will moisten the carpet and create some problems. First thing I recommend is to have the engine cooling system pressure tested to find, or rule out, any coolant leaks and then we will take it from there.