As the title says, this is a pretty thorough writeup of all testing, methods, and interpretation. Nice to have it all together.
Nice writeup of all oil testing methods, what they show, and how to understand the results!
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No offense, but I stopped reading when they started talking about 2 Stroke Engines!
dnewton3
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A bit dated, but overall not a bad article. This would be good reading for anyone wanting to learn the basics of UOAs.
I don't totally agree with all the condemnation limits, but that's subject matter for more advanced discussions.
I don't totally agree with all the condemnation limits, but that's subject matter for more advanced discussions.
I agree, I saw several minor points that could be argued for detail, but overall it doesn't oversell or under-educate.
Note that of all the different tests discussed, that many can not detect wear metals above 5-7 microns. Only test I saw in that paper was Ferrometry (Section 3.2.12) which said it can detect all ferrous wear particles above 0.1 micron. I believe a Blackstone type of UOA uses Plasma Emission Spectrometry (ICP - Inductively Coupled Plasma), and therefore is pretty insensitive in cases where lots of abnormal wear could be going on. You would probably see a slight uptick in the detected wear metals (ie, ppm per 1000 mile), but it wouldn't be a big red flag because that type of UOA is just too insensitive by only seeing a small sliver of particle sizes. This has been discussed in quite a few threads here, and a few examples given. A slight uptick was seen over the history of UOAs, and then further investigation (visual inspection of filter, visual inspection of machinery) showed a major mechanical failure was occurring.
There was one of my OA’s (IIRC it was the Motul Power 4100 15w50 VOA) that TestOil threw in a free ferrography test. Not very useful on a VOA, however
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