I just bought an old Craftsman 12G Air Compressor 106.154580 with twin cylinder pump. Since I can't find manual for this specific model and I don't know when oil was changed in the pump, I'd like to change it. Pump don't have oil glass gauge or dipstick. How much oil should I put it? Is Mobil 1 Extended Performance 10W-30 fully synthetic oil ok for the pump?

Do you remember how much was it back in the days? Do be honest I'm really shocked such an old compressor and it works so good.