AC O-ring Lube Type?

Hi,

The OP is talking about installing a Classic Air Retrofit system which is an R-134A system. Classic Air provides the compressor oil and I believe they use a PAG type. They are suggesting 525 mineral oil for the O rings only which is correct. An even better O ring lubricant/sealer is some stuff called Nylog. They have an R-134A specific type that works great in preventing leaks.

Using 525 mineral oil is okay since there is so little used to coat an O ring there is no oil interaction issues.