If its a sealed unit and the motor is inside the clyindrical domed unit(usually painted black) there are no seals between the compressor and motor to worry about. and any oil can only leak out where the gas has leaked out. The fan I suspect is something like a computer fan and a spray of aerosol OIL (Not the dreaded WD40) would do no harm. As already mentioned, you need to know the specs. for the machine in order to put the correct oil and gas weight into the compressor.