in the winter i bought a 96 dodge stratus. The mechanic i bought it from claimed he put a brand new compressor in it even showed me the old one, and the air blew cold, but of course it was winter so i didn't use it often. i live in florida and as the temperature changed, i turned on the a/c and only hot air blew out. i got freon put in it and it stayed cool for a day or so. any ideas on what the problem could be?