Stormin Mormon wrote:
One place I work, has a huge compressor. Three phase, from
what I can tell. Crankcase, and sight glass. I don't see an
oil level in the crankcase. The fill plug (big knurled
thing) didn't want to come out. I'll put a Channelocks on it
tomorrow, if I have time. Shine my minimag into the
crankcase, and see if I see any oil in there. Light up the
sight glass window from inside.

So, don't those beasts typically take ND-30 motor oil? Yeah,
they probably make something specific for crankcases, and
sell it in 4 ounce bottles so they can charge more.

I got compressor oil in a gallon jug.

Try a compressor shop.