[brian1971]

you can use ester (r12 oil) or synthetic(134a oil) .When you bought the compressor it has a tag in the box saying if it was dry.To be safe you have to pull off compressor and drain it.Then get oil specs on compressor and pour correct amount of oil into back of compressor.Was the ac system taken apart and flushed out you don't want to mix two different kinds of oil!