Mace,
Go here:
DEWALT D55270 : 5.5 HP 8 Gallon Gas Wheeled Portable Compressor
and here:
DeWALT Synthetic Compressor Oil (1 Quart) - 5130427-00
Synthetic oil is required for the compressor
Looks like Dewalt bought Emglo
Articles
I'll see if I can find out what oil the motor needs.