sdelasal,

On the air conditioning sites they refer to these kits as "Death Kits." They are not the death of the person using them, rather they are the death of the a/c system that they are used in.

At the time of most any a/c repair, R12 is the least expensive component in the repair. Usually the part that failed that is causing the system to be repaired is more costly.

Secondly, the 123 a/c systems are marginal, there is just not enough reserve capacity to tolerate the use of 134. If you run only on the highway in one of the cooler areas of the world you can probably get by with it, but it needs to be done correctly, not with a "Death Kit."

Good luck,