Just looking in the manual that came with my compressor and the oil specified is:
API SG/CD Heavy Duty* with * = (DeVilbiss Brand DV1721-040 can also be used in this compressor)

Grade info:
SAE 20 Below 20 degrees F
SAE 40 Above 32 degrees F

Don't know what you do if between 20 and 32... hahaha

I also don't see ISO 100 anywhere on the bottle I bought.  No idea at the moment what to do with the info "API SG/CD" and the bottle of stuff I bought.
 

11 minutes ago, inline6 said:

Oh.  That is interesting. Thanks Steve.  Looks like I should investigate API CC SAE and ISO 100 - consult my compressor manual and may need to remove and replace the $44 dollars worth of oil I just put in recently.  I'll investigate.

Frankly I didn't even notice that your compressor is a DeVilbiss. I just happened to notice the standards mentioned in the question. That's true blind squirrel action on my part.

4 hours ago, Patcon said:

I plumbed a small ball valve off the bottom of my tank but I don't go out there enough and drain it

If you aren’t using it very much, shut it down, and open the drain valve. 

Its rare it goes more than a few days without running. Its runs pretty much every weekend and occasionally during the week. I just need to be more consistent or risk an auto drain unit

I wonder what happens when you use ordinary engine 10w40 or so in a compressor?  I have my compressor since 1992 or so and only once changed the oil and about 10 x let a bit of water out the tank.  It's a cheaply 2 HP less than 10 gallon tank ..  and the first thing i do when the day comes that there is no air.. is... buy meself a new one! 😉 

So i'm not gonna change the oil but what happens if you would use 10w40? (engine oil)

3 hours ago, dutchzcarguy said:

I wonder what happens when you use ordinary engine 10w40 or so in a compressor?

I'm no oil expert, but as I understand it, the general theory / consensus is there would be increased wear on the moving components like the crank bearings. Goes like this...

The difference between the "detergent" and the "non-detergent" oils is the ability to suspend particulate contaminants in the oil. The automotive oils (detergent) contain additives that are designed to intentionally suspend particulate contaminants in the oil. The expectation is that those contaminants will be removed from the system and trapped in the oil filter.

The non-detergent oils are used in applications (like your compressor) where there is no oil filter. The intention is that the particulate contaminants are NOT suspended in the oil, but instead sink to the bottom of the crankcase where they don't do any harm. Those contaminants are removed from the system when you change the oil, or every twenty years when you break the crankcase open and scoop them out manually.

If you use detergent oil in something like your compressor, some of the harmful contaminants will be suspended in the oil and continuously circulated through the system where you don't want them. Better to let that stuff settle to the bottom than have it end up in your main and rod bearings.

Thanks CO!  I bet then that the hydrolic oil in my car lift is also NON-detergent oil!   In 1995 when i bought my lift, it worked a year or 2 and then i restored it by putting in a brand new pump and new oil and seals..  I know the oil is the right stuff as the firm that delivered me the new pump also delivered the oil.

As you like stories!

I phoned that firm when i needed the new pump.. the old one was 10 years old and used a lot..  When i asked the guy on the phone and he repeated the number of the pump someone on the background sayd: YES! we do have a pump like that! It's been laying around here for Ages!! 

Then as he was also hanging around in theire warehouse looking for the pump to be sure, he came back on the phone and told me, YES we have a pump for you! I told him: Yes.. and it's laying around there for AGES!  Hahaha, he laughed, did you hear that!!  YES i did and i'm in need of a discount haha.. i believe it was about 75dollars that pump.. (150 guilders then)

It's still working till this day! (It's a spanish brand 3 or 3,5 ton lift. ISTOBAL )

Haha!  Been laying around for ages is always nice for making a good deal. Nice story.

And yes... I would also assume the hydrolic oil in your lift is NON-detergent.  

The lift I have uses atf as the hydraulic oil (atf is hydraulic oil by the way).

I used to own a 1948 Chevrolet dump truck. The dump box, manufactured by Heil, used 10wt non detergent motor oil for the hydraulic fluid.

My 1948 Ford 8N tractor uses tractor hydraulic fluid, which is a hybrid hydraulic fluid/gear lubricant as the tractor hydraulic section is common to the transmission and differential.

So, three different types of fluid to accomplish essentially the same thing.

Oh, and the only vehicle I own that has an automatic transmission, my 1995 F150, uses atf (a specialized hydraulic oil) in the automatic transmission (a specialized hydraulic pump).