the oil does not dissolve in the gas! if you get a catastrophic leak then some oil will escape, the seal on automative systems is a ceramic seal similar to the one on car water pumps, if you dont use it during the winter some leakage occurs past the ceramic face and steel face, most car manufacturers recommend that you run the system once a week to make sure that hte seal is kept sealing see here for more definitive info http://www.carcare.org/climate_control/refrigerants_oil.shtml stu