DieselHead,

I hope our friend Jovan takes no offense at my response, but proceed EXTREMELY CAREFULLY regarding ANY R12 "replacement". Most of these blends are explosive. If a compressor were to lock up making a spark, you or your family will be sitting inside of an artillery shell. Yes, this has actually happened!

If you can find the leak(a flourescent dye is the best approach for this), and fix it, recharge with the gaseous gold called R12. It will do a much better job, eliminate problems and you will be much happier with the result. I have converted several vehicles to R134a and have yet to be happy with one. The 123 Benz just does not have enough condensor capacity to give you an efficient heat exchange with the less efficient R134a.

If you insist on changing to R134a, I would suggest flushing the system piece by piece, changing to green o-rings everywhere, replacing the filter-drier, using ESTER oil only, pump down for 24 hours, and charge with a volume of R134a that is 85% of the amount of R12 specified. When you screw the R134a adapters on the charging ports, don't forget to take the schrader valve out of the R12 port first.

Good luck,