Any good AC shop will not touch a car with substitute coolants if you have a problem. It will contmainate their recovery tanks and cost them big bucks. If you have a leak from one of the substuitute/approved coolants, the different components leak out at different rates and then you have no idea what you have in the system. Most folks will be better off in the long run using R12 or R134.

I was skeptical too about Autozone carrying R12 at $15/ can. I assumed that it was something that said "12" on the can like Freeze 12 which will never see the inside of my garage let alone the inside of my AC system.

Len