converting from mineral to POE there should be no more than 5% mineral oil left in system
and they are not compateable.
These were basic rules during the refrigerant retrofits in the 90's for refrigeration
Old thread, but couldn't help it, made me curious. With elvis66 MIA, I think indy2000 has called it on this one. No need to worry if level present and not tripping.
One thought tho... POE has more detergent qualities and is more miscible than mineral oil. It will disolve in and out of refrigerant faster than MO especially in HCFCs. That being the case, "foaming" at the crankcase is not unrealistic.