Although my question is not of a k-5 i have found there are some very smart mechanics on here so that is why i am asking here. i own a 1990 cadillac and it has run out of freon. I know that this system was born using r-12 but I was talking to heating and aircondtioner man the other day whom said he idnt see any reason that a guy couldnt just put in r-134. i dont know to much about air condtioning and that is why I am asking you guys. The reason I am wondering is because once again the cadillac has run out and i dont really have the cash to go out and buy 30lbs. and i dont want to spend the kind of money proplr want for 1lb. cans. anyway thsanks alot.