Shelf life of oil, revisited

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Staff member
May 27, 2002
Guelph, Ontario
I know we've discussed the shelf life of oil here in the past, and that it's about 4-5 years, but I'm wondering what exactly happens to the oil as it gets that old? And what about oil that has been sitting around for 2 or 3 years, does it begin to show signs of degradation compared to when it was freshly packaged? I think with the number of us on here who are storing a lot of oil, this is something of concern. I can't help but wonder if the oil that I'm saving will be just as good in two years as it is right now. Would older oil not be able to handle longer drains for instance?
Many European manufacturers specify 5 years on oil can labels. And only once I could met oil cans which were bearing (on additional label, if I am not mistaken) recommended storage temperature: 0-20 C or 0-25 C. This was Mobil1 products. Apparently positive temperature range is recommended in order to avoid a condensation. It was mentionned somewhere (seems links at NORIA) that oil manufacturers do not have an unanimous opinion on this subject, but some of them claim that shelf life may be reduced by: - 3 times at storage below 0 C - 2 times at storage over 35 C (or 30 C).
I'd like to know this as well, but would also like to know how temperature fluctuations affect an oils cold properties. My oil is in our garage where the temp is as low as 15F in the winter. Dave
I've only ever posed that question to a tech at Redline who informed me that their oil doesn't have a shelf life. Was he telling me the truth? I can see some of the components possibly separating out of the mix over time, but would it ever be to the point as to make the oil unusable?
This was discussed by Pat Goss on his segment of the Motorweek TV show. Pat Goss said motor oil does not go bad, it just goes out of specification, ie don't use 5 year old oil in a new model car. Just what one expert had to say.
What about when the oil can (bottle) has been opened ? My 3.4 engine needs 4 litres. Pennzoil jugs are 3.78 liters, so I need to open a 1 liter can to fill to the proper level. Is the oil in the can will loose some property ?
Opened containers of oil should be fine so long as they're recapped tightly during storage. It may darken when exposed to air (a bit of oxidation, I presume), but this is not supposed to be of significance, especially when compared to the much, much harsher environment routinely experienced inside an operating engine. When you think about it, a bulk oil drum is a big, half-empty "oil bottle." From what I've read, it appears that the Pour Point enhancers in oils MAY degrade to some degree when exposed to severe cold and/or temperature cycles, even when bottled and sitting on a shelf in winter. Not sure about this, but that was the impression I got. A side note, STP claims an "indefinite" shelf life for all their gas and fuel additives, so I assume the same for most brands. [ January 14, 2004, 09:26 PM: Message edited by: TC ]
Glad you folks brought this up for discussion again. Good thing, too...after discovering this site I started buying all kinds of motor garage looks like Imelda Marcos' closet. Then I started parsing the UOA's and went geek on extended drains. Add 1 and 2 together and I have enough motor oil to last until the sun burns out. Glad to know I'll actually get to use some of it [freaknout]
Originally posted by gavinl: I got a reply from AMSOIL stating there's no expiry on their oil too! [I dont know]
I also asked Amsoil and was told by Tech. Support that there are no standards but that the widely accepted rule is 2 years. Guess they didn't want me to send in the discount payment once, buy a tanker full, and never pnone them again?
Well, oil survived underground for millions of years right? Just because it was cleaned up and had a few things added to it shouldnt shorten its lifespan.
EVERY MSDS I've looked up on the internet ALWAYS lists long term stability of finished motor oils as "indefinite" when stored sealed in the same temperature range suitable for human habitation - translation: longer than you'd want to worry about. I go with Pat Goss - motor oils go out of current spec as the API and auto manufacturers develop new standards. Motor oil is not fresh produce or meat and doesn't rot. (Fact is, petroleum's the end product of rotted fauna and flora after being processed for several million years under high heat and pressure...) [ January 29, 2004, 12:01 PM: Message edited by: Ray H ]
Keep in mind that some additives are not liquid, but suspended solids. For example, Molybdenum disulfide is a solid. Yes, an extremely fine powder but I'd guess that over time it would settle to the bottom of the bottle. Early versions of this additive settled quickly to the bottom. If you decide to keep your oil for a long time, you may want to shake it up before using it.
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