Hi,

I am thinking about topping off my freon in my R-12 system. Before I got adding anymore R-12 to the already charged system, I want to give it a boost of oil charge so the system doesnt seize on me. What oil is used for an R-12 system?

Any help would be greatly appreciated.

Thanks,

Mineral oil, you may also use Ester oil.

Is there a certain number for the Ester oil? If I remember right from the last time I saw them at a parts store, they had different numbers of Ester?

You're thinking of PAG oil, Ester is Ester.

use r-12 mineral oil for the system. Do not use ester or PAG in any R-12 system. the oils will react together and gum up.

use r-12 mineral oil for the system. Do not use ester or PAG in any R-12 system. the oils will react together and gum up.

You're thinking of PAG as well, Ester mixes well with mineral oil and does not gum up, that is an old belief. The fact that Ester mixes with mineral is the main reason it is the recommended oil for use in retrofits, been using it myself for several years.

Nonetheless, use mineral oil in R12 systems if you have it, but Ester will work in a pinch.

interesting, mixed the two together on the bench and then measured Brokkfield viscosity and it went very thick. Not sure how it would react at cold temperatures. Don't have a cold box to try it in. Can you send me a link to SAE location where it discusses using the oil together? Thanks