I added motor oil in my 40400
by Ahmad Al Sharawneh
(Raleigh nc USA)
I added motor oil in my 40400 model, now the oil coming out from the overfill
What you refer to as the overfill is, I suspect, the oil fill & vent cap for your compressor.
Motor oil has additives, one of which may be detergents, which suggests that, if you did not overfill the air compressor, the running of the pump in a bath of motor oil is causing the oil volume to expand and blow out the oil fill tube.
If you used motor oil, drain the oil and replace it with compressor lubricating oil.