Many people think the additives in motor oil settle out after some time. I had an old bottle of oil in my garage. I had an oil lab run samples of each level in the bottle to shed some light on the question.
The samples that were sent to the lab were TOP, MIDDLE, and BOTTOM.
When the samples came back from the lab I was shocked !!
Will you be shocked?
Watch the video to find out!.
UPDATE: Below was my answer to a question on bobistheoilguy website from someone skeptical of my results. It will make more sense if you watch the video first.
I think everyone agrees there is some sort of grey stuff people find, as I did, on the bottom of bottles of oil. As the test results show, it is not any of the normal additives settling out because the tests show all the additives are still in the oil and in nearly identical amounts from top to bottom. If the gray stuff was one of the normal additives that gets tested for and ALL of it had settled then obviously none of it would have been left in the top sample. And since I stirred up the gray stuff so it was mixed into the bottom sample, the bottom sample would have been very very high in whatever additive or contaminant the gray stuff was. Yet that was not the result. So we know that when you mix it into only the small remaining bottom oil that whatever it is does not show up as one of the things (good or bad) normally tested for.
What I think we can say with reasonable certainty for this oil is this...
the additives considered important to regular motor oil and which are tested for as part of a routine oil analysis did not settle out.
we know that the gray stuff is not one of the contaminants which are tested for as part of a routine oil analysis because it did not show up in the bottom sample which would have had all of it mixed in for the sample tested. So it's not dirt (silicon) which had all fallen to the bottom. It's not iron, it's not aluminum, etc. .
In a quart there are about 15,000 drops of oil. A drop in a quart is the equivalent of about 66 ppm (parts per million). If you saw the gray dust in the video and imagine you could manage to scoop it all up I doubt all of it together would even be the volume of a single drop of oil. But if there was a full drops worth of gray dust that means the amount of it in a quart of oil is no more than 66 ppm. That small amount is unlikely to be a problem.
We can make an estimate of the size of the gray particles. Based on info here (www.machineryl...) particles large enough to be damaging (20 microns) would have settled to the bottom in less than an hour in ISO22 turbine oil. That's similar to 0 weight motor oil. Even if it took 10 times as long to settle out of common weight motor oil it would still take less than a day. Assuming this gray stuff took months or years to settle out that would mean it is surely under 10 or less microns, very fine material indeed.
My conclusion about the gray stuff in this particular brand/bottle is that there is nothing to worry about because the expected particle size and quantity are both so small. But if someone is worried that the gray stuff is bad the best thing to do with oil that has been sitting is DON'T SHAKE the bottle. The good stuff hasn't settled out and the potentially bad stuff, the gray stuff, is stuck to the bottom. Don't shake it and the gray stuff will stay stuck to the bottom of the bottle and the good stuff will be in the engine.
On the other hand if you think whatever it is is good stuff that has settled out go ahead and shake the bottle.
In either case you'll only be excluding or mixing back in about 66 ppm of something so probably safe either way.
UPDATE: Jan 2023. The Motor Oil Geek did a similar look at old oils and found some disturbing stuff that had settled out, far more than settled out of the quart of oil I used. His old oils were considerably darker than the old oil I used. From my results and his results it seems safe to say that if your old oil is dark, don't use it. If a lot of gunk has settled out, far more that in my sample, don't use it. If, on the other hand, the color seems normal and you don't see lots of gunk you probably don't have a problem and it's safe to use. Only you can make that call.
Here's a link to his video of the old oils. • EXPIRED: When Does New...
17 окт 2024
