Does Machine oil go bad?

[tech4]

Does machine oil like 3 N 1 or Zoom oil go bad if sitting on the shelf for a long time? I know some motor oils will congeal with age but not sure about the light machine oils. I have some Zoom oil on the shelf that has been there for years and trying to decide if I should just pour it in the recycle oil tank. Also anyone know is it OK to put transmission fluid in the used motor oil tanks?

[markkw]

If it looks good - no water/condensate or milkshake, doesn't appear separated, congealed or waxy and it doesn't have acidic or sour sulfur type smell, it's probably good. I wouldn't use it in a critical application but for general purpose I wouldn't hesitate. If it's really old, 25-30 years, remember the oil may have some lead, chlorine and/or sulfur intentionally added to it, that was common to good additive packages. Thing you're looking for is a "sour sulfur" smell, if you're not familiar, it's hard to describe and not to be crude but it's sour enough that you'll "feel" it in your nose. If you have an oil recycler in the area, stop in and ask them if you can get a sniff of "#2 oil tank bottoms" - that'll be a super concentrated form of the smell you don't want to smell. Only takes one time, you get a snort of it and you'll never forget it.

Oil is oil as long as it's petroleum base or petroleum compatible synthetic and does NOT contain chlorine! Waste oil must be below 1000ppm chlorinated halogens, it doesn't take a lot to get above that limit and if the tank you're dumping into goes over 1Kppm, you're going to get charged, a lot, to have the oil pumped. Same thing if you mix oil types like non-petroleum compatible synthetic, brake fluid, soluble oil, ect. Anything that isn't petrol base or petrol compatible will bugger-up the works and cost you a small fortune to dispose of. When in doubt, keep it separated! If you don't have an "approved" container, I cannot tell you that HDPE plastic jugs will suffice for temporary use (milk jugs and such, look at the bottom, the type of plastic will be identified) I can't suggest that though, you should always seek out an approved waste oil container.