This is a classic example of how folks don't understand how to properly read a UOA.
There are two basic, fundamental concepts:
- oil health
- engine wear
BOTH are implied by the UOA.
In regard to oil health, we look at vis, oxidation, FP, TBN, etc and determine how long the oil still might be serviceable. Changes which occur do NOT mean that the engine is at risk of eminent demise; they only mean one should watch closer for the effects of wear rate changes. Just because FP drops, or dilution increases, or TAN crosses TBN does NOT automatically mean the oil is unfit. It only means the oil has changed and the wear rates MIGHT change, and the only way to know is to track the wear, relative to the oil parameter changes.
In regard to the engine itself, the metals can tell us about normal and abnormal wear. Steady numbers in the expected ranges generally indicate all things are "normal". Whereas spikes and upward trends can indicate something is wearing abnormally. Some upward trends are typical; Fe often tracks with miles accumulated as well as is a function of loading. But the other metals are pretty much only reactive to adverse conditions (the only exception being chelation from chemical reactions such as leaching Cu out, etc).
The only thing that would give me pause regarding this UOA is that there's no real history which the 26k miles built upon. I do NOT advocate for blindly extending OCIs out to 25k miles or more. You want to build a history of engine health and understand how well it tracks to "normal" expectations. This UOA, if we accept it's claim of 26k miles, is very impressive, but it was a risk; we all know that. Had there been a UOA of this load at 10k miles, then 15k miles, then 20k miles .... that would give confidence that the long OCI was warranted.
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The Fe being so low, and the insolubles being so low, would make me really doubt the 26k miles. Not that the OP is trying to dupe us, but maybe an OCI sneaked in when he wasn't looking? I'm not really familiar with the Mobil 1 additives; does this appear to be as claimed, or could it be another lube from an unknown OCI?
Looking at this VOA
https://bobistheoilguy.com/forums/threads/mobil-1-triple-action-5w30-ep-voa.367619/
it appears either the formulation changed, or the oil is not as claimed?