there is a water leak from the heater radiator (radiator core)loose pipe.My understanding is that the pipe is for the AC

 

moremj, you have 2 different "radiators" in there. ONe is to heat up the air (has engine coolant in it), the other is to cool the air (has freon in it). With all this being said, when you run the system, because you are changing the temperature of the air, it is possible for you to also have the humidity in the air come out and it will pool in the bottom of your heating/cooling system and it will drain out the bottom via a drain that is there.

I guess my question is whether the water coming out the bottom of the car is clear or if it is tinted with a color (normally green or orange). If it is clear, then this is normal. If you are loosing coolant and/or you have colored water coming out, then your heater core is bad and it will need replacing.