I have Robinaire 3 cfm 2 stage AC vacuum pump, been using it for mine and family vehicles for almost a year now. It came with a small bottle of oil when I bought it. Figure it's time to replace the oil, but I don't want to pay the high prices for vacuum pump specific oil. Don't have the manual handy to tell you what the requirements actually are (maybe ISO 68/100?), but I'm hoping compressor oil or some other more common oil type can be used as a substitute. Anyone have experience with these?