Alrighty, i have a 1995 f150xlt 302 5.0. Everything runs sort of okay except summer is approaching and whever i turn on my A/C coolant leaks from somewhere. Now i cant smell it through the vents, my ac still gets really cold but when i step out it just blasts you in the face with that sweet syruppy smell of coolant. So i had a buddy of mine start my truck up and turned the AC on full and it didnt leak we checked and waited for the smell but it mever came. It seems to only leak when ive been driving it. And no i know its not condensation

 

Can't think of any connection between running the A/C and a coolant leak.
How much coolant are you having to add?
Somewhat unclear - are you seeing a leak that you can't tell where it's coming from, or just smelling a leak with no visible drips found?
Have ran into a small pinhole in the radiator where one could smell it, but I guess it misted or the fan blew it out or it evaporated fast enough that it was a pain to find. A pressure test with the engine cold and off may help here.
Not smelling it in the cab would tend to eliminate the heater core possibility.
Good luck and keep us posted on any additional news or findings.

 

Did you have work done to your a/c in the last several years? As weird as this might sound, I had Firestone pretty much rebuild my a/c system last year. They replaced some hoses and eventually the compressor. When I run it, I also get that sweet smell of what I think is antifreeze. But I have not had to replace any coolant in my truck for quite some time. Matter of fact, that is kind of a new feature for me. I had to replace my radiator three or four months ago and have not had a coolant issue since. And my a/c works fantastic. So I feel it is something the new system is putting out and not the antifreeze. But I could be wrong. I just haven't found anything.

 

Pressure test the cooling system and start looking.