OK, potentially noob question...... what's the difference between R12 and R134a? (anything to do with the difference in 96-98, 99-00 vent systems?) what would the benefits be to doing a convert, and can one be done on a 97 civic (assuming it involves more than just changing the coolant chemical?)

Reminiscing about my AC on the extremely hot drive home today I remembered that before my AC went to crap there were a few times I noticed that when I had it on it looked like dust or even faint smoke was coming out of the vents, it didn't have any scent or anything. AC worked fine while it was doing this, and it did for a summer, by the time the next summer rolled around the AC had crapped out. I thought the stuff was likely dust/dirt from the vents, but who knows...

Anyone heard of this? I just can't stand the thought of paying someone 1K+ to fix this.