Originally Posted By: Cujet
https://www.avweb.com/news/maint/185087-1.html
https://www.amsoil.com/techservicesbulletin/MotorOil/TSB MO 2004-07-02 Fuel Dilution.pdf
wear particle sizes are often 5 to 10 microns and larger. So, why does this matter? Size is important because the most commonly used test method to assess active machine wear - elemental spectroscopy - has a limit to the size of particles it can detect, elemental analysis can't detect particles larger than 3 to 8 microns in size, rendering it useless in situations of advanced machine wear, or where the failure mode naturally generates larger particles, such as fatigue or severe sliding wear.
Particle contamination accounts for 60 to 80 percent of all lubrication-related failures.
I understand people here put an awful lot of faith in UOA results. The fact remains, UOA is a tool and nothing more. There are many aspects of oil that are not tested with UOA. It's not uncommon to see failed engines that exhibited excellent UOA results.
I recently replaced an aircraft engine that had acceptable UOA results, ran quite well, and had nearly self destructed inside. It had excessive camshaft and rod bearing wear.
It's also quite common to see engines with marginal maintenance last for decades past where some would cry heresy and recommend overly frequent efforts. To wit; over-maintaining something has never proven to prevent any catastrophic event any more than marginal efforts have caused them.
UOAs are direct views of the lube health. They are indirect views of the equipment health. But they are, by far, the cheapest and easiest manner to view/track wear trends. They certainly not perfect, but nothing is.
The point I make is that NO ONE complained about the wear rate of 2.0ppm/1k miles in some of those engines, but they harbor great disdain for EB engines with high fuel, even though they exhibit the exact same wear rate of 2.0ppm/1k miles.
If one wants to profess that the UOAs do not disclose all issues (and I'd agree to some manner that is true), then why not complain about ALL UOAs? Why do some folks ignore a wear rate of "X" in some engines, but other engines with the same wear rates of "X" are scrutinized with impunity? Can you say "bias"?
Changing the oil more frequently in this engine isn't likely to reduce the wear rate.