Because it is "European Car formula," is this the same AW/DI package as the 0w-40, just matrix blended to a different multigrade?
Mobil 1 5w30 FS European Formula
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Stronger...in what way(s)?
Stronger oil film between moving parts.
Oils are probably the same except for viscosity, but the 5W30 can't claim SP due to the zddp levels.
Why iron ppm numbers are NOT good wear indicators.
http://www.lubrigard.com/products/literature/WC-PQ-ANALYSIS.pdf This is an article from WearCheck about PQ index. I'm posting it here because it shows how the wear numbers on most UOAs can't be trusted. The article shows two examples of UOA results: one with 286 ppm of iron, and one with 12...
bobistheoilguy.com
@bluesubie - That is a great post. UOA's may give a false sense of security, even when catastrophic wear can be occurring.
My first thought is those who do extended OCI's and are feeling safe with the PPM #'s being low, even though the mass of the undetected wear metals could be indicating catastrophic wear.
Here is that first post from the above BITOG thread. You can reference the whole thread by the link above.
http://www.lubrigard.com/products/literature/WC-PQ-ANALYSIS.pdf This is an article from WearCheck about PQ index. I'm posting it here because it shows how the wear numbers on most UOAs can't be trusted. The article shows two examples of UOA results: one with 286 ppm of iron, and one with 12 ppm. If you ask anyone on this forum, 12 ppm is totally fine and 286 ppm indicates a serious problem developing. However, once the PQ index is factored in, you can see the reality is exactly the other way around. The 286 ppm example turns out to have no abnormal wear whatsoever, whereas the 12 ppm example looks catastrophic. How could this be? Most UOAs are done with a method that counts the number of iron particles that are in a certain range of sizes. If you have particles that are bigger or smaller, the lab can't detect them. PQ index, on the other hand, measures the mass of iron in the oil. No matter how big the particles are, they will be counted. In the article, the 286 ppm of iron turned out to be made up of of extremely small particles, indicating light corrosion. This means the oil is overdue for a change, but it doesn't mean the engine is wearing out. By contrast, the 12 ppm of iron turned out to be hiding a very serious problem: the engine was wearing badly, but it was chucking out particles that were too big for the standard UOA to detect; hence, the iron number was low even though the wear was catastrophic. FWIW.
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That doesn't make sense. If a lab is counting particles they don't know if they are iron or not unless a SEM-EDX is being performed, and I doubt that is "most UOAs." And if they are talking about ICP then there is no lower limit to a particle size. Atoms will register on a spectrographic analysis, and in fact that is what it is designed to do. ICP does not count nor measure particles.
What the article is saying, is the UOA only measures particle sizes in a certain size range. So any particles smaller or larger than the starting and ending points of the range will be invisible to the UOA and go undetected. Those large particles of wear metals which are too big to be measured by the UOA and the total mass of all of those undetected sizes of the wear metals is where the danger is. So lets say a person is doing a 25,000 OCI, and they see low wear metals, the wear could still be catastrophically bad if the larger wear metal particles are in the oil but are going undetected by the UOA due to the size of the particles being greater than the range the UOA detects.
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That's part of my point. A typical UOA uses ICP to measure iron, and there is no lower limit to particle size. So therefore no "range" and no ending point, nor will it be invisible.
But the rest is correct. We performed acid digestion on the samples which achieved the same result.
UOA's have a number of problems.
[1] The standard deviation of their results (which can be thought of as their margin of error) is large, so you can't compare different oils, etc, as any wear metal reading within the standard deviation has to be considered equal.
[2] UOA's don't measure how dirty/decomposed the oil is.
For example: Dirty/sludgy/lumpy/clumpy oil which is gumming up your piston rings and oil control rings would likely show up on the UOA with low wear metals.
[3] The point raised in the article below (low wear metals could mean catastrophic wear):
Why iron ppm numbers are NOT good wear indicators.
http://www.lubrigard.com/products/literature/WC-PQ-ANALYSIS.pdf This is an article from WearCheck about PQ index. I'm posting it here because it shows how the wear numbers on most UOAs can't be trusted. The article shows two examples of UOA results: one with 286 ppm of iron, and one with 12...bobistheoilguy.com
In conclusion,
I believe it's better to save your money and never do a UOA, and instead spend the money to have a trusted mechanic remove your valve cover to show you the cleanliness of the top of your engine (and put new valve cover gaskets in while he's doing it to prevent future leaks).
If you see a lot of sludge/varnish, you may wish to shorten your oil change interval.
As the owner of many personal items with internal combustion engines, as well as 34 years of also owning semi trucks and heavy equipment, not once have i sent in an oil sample.
Honestly looking back now, ignorance was probably the best thing for me. I wasn't stressing over some report, just changed oils, and ran them.
Honestly looking back now, ignorance was probably the best thing for me. I wasn't stressing over some report, just changed oils, and ran them.
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