Does Motor oil have a shelf life? (1 Viewer)

Joined
Feb 4, 2015
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Well i stopped by a buddy's shop today, he was in the process of cleaning out some of his storage cabinets. On one of his work bench's i noticed 3 unopened cases of 10W40 motor oil. I ask him what he's planing on doing with that oil.

He tells me he's going to take it to the parts store to recycle it. I'm thinking to myself why would you want to recycle new unopened bottles of oil.

He told me that he read on line, that if motor oil is over 5 years old, that it's no good to use anymore. I can't say I've ever heard of this before, but then again, maybe that's due to the fact that oil never sat around my shop for years, it always got used right away.

So when i got home i went on line and looked this up myself, and sure enough, there were a few different web sites that said you should not use oil if it's over 5 years old. They also said that storage temps in excess of 80 degrees will shorten the shelf life of not only motor oil, but also grease, gear oil, and trans fluid too, to less then 5 years.

That temp thing could be a real problem for Mud members who live in the desert southwest where temps in the summer time get WAY above 80 degrees. I"m kind of thinking these web sites may be financed by the major oil company's, and their view point may be a little self serving to help sell more motor oil.

So what do you think, should you throw away all the motor oil, grease, trans fluid, and gear oil you may have sitting in your storage cabinet if it's over 5 years old. Or sooner if you live somewhere were it gets above 80 degrees in the summer time?
 
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Joined
Jun 20, 2007
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479
Location
Provo, Utah
For all intents and purposes, oil has a virtually endless shelf life. Yes, it can degrade over time, especially multi-weight oil. Stabilizers become less effective. That being said, for average automotive use, there's not enough of a difference to matter. I'd wager that it's worse for most older engines in most conditions to use a newish paraffin base oil (which have been largely phased out) than an old single weight oil. Mud being the place it is, I'd also wager than there are more than a few who are anal retentive enough to throw out old oil and grease that isn't bad other than the expiration date. HTH.

PS - As a fun little fact; most canned food has an exceptionally long shelf life as well (40+ years) as long as the contents are canned properly and the can isn't compromised in some way.
 
Joined
Dec 10, 2007
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7,506
Blacktone Laboratories collected some very old NOS oil from fleabay IIRC, 40+ years old, and tested them. The additive packages were different, but they said you could put the oil in your engine and drive it.

Cleaning out my garage once I found a bunch of 10-15 year old oil (different brands/weights), didn't want to toss them, so used them along with a new filter and a mild engine cleaner (? Rislone) for a few hundred miles then dumped it and refilled with the usual oil I use with another filter change. FWIW.
 
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