I guess I need new freon in the AC system. Or a recharge, I know that since 1995 the ozone friendly 134-a had to be put in new cars. Obviously my '91 has CFC-12. What will be involved? Can they just change the freon, or do they have to change the compressor, etc? My Chilton repair book recomends that all cars with AC be maintained, and to do that it is good to run the AC for 5 or 10 minutes each month to keep the seals from leaking no matter what the season. My dad never did this and it blows warm. I did follow this guideline for my previous old car for years and it still blew cold. Later this week I will get a price quote from Midas, etc. Does anyone have experience with this??