O/T: Sorry, engine oil again. Does sealed, unopened Mobil1 synthetic go bad?

[JRouche]

Went to change the oil today and had five quarts of Mobil 1 synthetic from a few years ago. I also had a 5qt bottle of it I was gonna use. The 5qt is only four years old vs maybe eight.

The old oil looked very dark, almost like a dark red, like it was used cept reddish not black.

I know what you will say, dont be cheap and toss it.. I agree. The question is does it go bad and why? Is it cause its a synthetic and not Dino?

Of course mobil put a shelf life on it. Thanks for any input. JR

[Cuttings]

This is not quit what you are asking - A number of years ago I had the transmission oil changed in a Dodge car I owned and I was informed that the new oil was synthetic and it would go to a much darker color very quickly once I started using it. I was also told not to worry because this was normal. This was automatic transmission oil, not engine oil, but it was synthetic. I would try to find a support email address for Mobil Oil and ask them. Regular oil does not go bad just sitting around but I don't know about synthetic.

[Cuttings]

I just goggled shelf life of Synthetic engine oil and Exon Mobile says it has a shelf life of 5 years. Here is the link <https://www.bing.com/search?form=MOZLBR&pc=MOZI&q=SDoes+synthetic+engin e+oil+have+a+shelf+life+%3F>

[darryl]

What is the shelf life of crude oil? Not trying to be snarky here- I'd say the longevity of the oil is more related to additives falling out and moisture absorption through the walls of the container than any intrinsic decay property. Any oil newer than say 10 years should have a fairly up to date additive package- and if it meets the criteria for your engine it should be fine. Shake it up well to mix any additives that may have come out of suspension, and don't worry about anything else unless the container has been open. That's my take on it-

[JRouche]

Thanks Cuttings! And D, I didnt think to shake it, well I half heartedly shook it just out of habit. I should have gave it a good throttling. It looked real nice, felt real nice. Just really dark.. Thanks for the input guys. JR

[J Tiers]

Natural mineral crude oil has been pretty stable for a few hundred thousand years, according to all I have read. When processed, the processing (catalytic "cracking", for instance) may make changes the structure of the molecules in some cases, perhaps not in others. The changes may or may not affect the stability.

The "synthetic" oil was "engineered" to have different characteristics. Just how those characteristics are provided in terms of the structure of the oil molecules I do not know. The molecules are created in a certain range of lengths, with additive elements or molecules attached, perhaps others removed, etc. It is possible that some "synthetic" oil has a molecular structure which is stable in the short term, but begins to alter over time, losing its intended characteristics as it alters.

It makes a lot more sense to assume that a "synthetic" oil may not be as stable as a straight mineral oil which has been extracted from crude oil. But some "processing" of regular mineral oils, which falls short of being "synthetic", may also alter structures and shorten shelf life. Same for the additives that are put in the mineral oils, which may not be as stable as the base oil stock is..

And, synthetic oils can be MORE stable in some characteristics, such as viscosity, than mineral oils. So those characteristics may change or "degrade" much less quickly than a mineral oil.

If Mobil says 5 years, that suggests that somewhere between 5 and maybe 8 years is the point where you might not want to depend on the full set of good characteristics. That would go for either "synthetic" or "mineral base" oils pretty equally.

[BCRider]

Perhaps the color is related to a change in their additives between the two batches you have?

[Mcostello]

Maybe it's getting rusty.

[JRouche]

I wanted to put pictures, I think some folks have bandwidth limits so I want to limit my pics. JR

Old new bottle of engine oil vs a new old azzed can five years old. No I am not cheap, really, its 6 bucks a can.

Yeah, its in the engine.

It looked good. JR

[JRouche]

I think its fine?? JR

[SLK001]

You're comparing apples to oranges. The 5 quart "Mobil 1" isn't Mobil 1, it's Valvoline - and, they're different weights.

Both oils look okay to me. You should be good to go.

[eKretz]

I wanted to put pictures, I think some folks have bandwidth limits so I want to limit my pics. JR

Old new bottle of engine oil vs a new old azzed can five years old. No I am not cheap, really, its 6 bucks a can.

Yeah, its in the engine.

It looked good. JR

I'd agree that the oil on the right looks a bit reddish/brownish, almost like it's oxidized a bit or something. Might have a shorter useful life in the engine. Could try one of those Blackstone tests on it or whatever they're called after a while and see what they say about the results.

And "old new," vs. "new old?" Whaa? Also, them there's both bottles, man, neither is a can. And, we've now run the full gamut, with a picture of your mug. With that, I take my bow....

[A.K. Boomer]

Wow that's dark --- I would have saved it for the lawn mower or something, you can always find uses for "questionable oil" but that stuff would not see the internals of my car engine... even if just for being able to judge when my oils getting dirty enough to dump....

[old mart]

When I got my present car about 5 years ago, I bought oil and filters to change halfway between yearly servicing. It did not get used because I had no chance of ever reaching the filter which was at the rear of the engine. It is German made fully synthetic 5W30 and it has the date of manufacture and shelf life on the containers. Last year I bought one of those cheap 12V pumps for draining through the dipstick hole and it worked very well after I had given the engine an hour to cool of a bit. I did replace the oil with recently manufactured stuff and took the unused older oil into the museum and the Smart & Brown model A loves it. It hasn't darkened with age like some of the other examples shown.

[Guido]

Plastic bottles? At Wallies yesterday, name brand motor oils were 12 bucks/qt, and hanging on a hook. Yep, hangin on hooks, clear, baggy, screw capped bags.