Alright, I scored an old small belt driven one, for real cheap. Brought it home, replaced the hose and it's going well. I can turn it on all night in the garage and it can NOT be heard from outside

. It says it can get up to 100 PSI but I can only pull it up to 90 max. I tried to shoot some nails and it went well. Now, I can't find any place to replace or refill oil. Any one know about this air compressor?
It is a Magna Force. SCFM is between 4 to 7. Model number is 64A150-14. It looks just like the pic below. I searched the net but can't find manual.