I would disagree; it is Mobil's implication that 15k miles is doable.
Here are some quotes directly from the EP page:
Our most advanced full synthetic offers unsurpassed wear protection to help extend engine life and provides protection for 15,000 miles between oil changes – guaranteed.
What the Period of Coverage Is
The Mobil 1 Extended Performance limited warranty is valid for 15,000 miles or your vehicle’s OEM recommended oil change interval, whichever is longer.
Additional requirements for Mobil 1 Extended Performance include:
Oils must be put in service not later than five (5) years from the date of purchase; and
an oil change must be completed every twelve (12) months.
As you can see, they CLEARLY state that 15k miles, or OLM, whichever is LONGER. But, they have a few caveots; must start the service within 5 years of purchase, must OCI at least every 12 months.
Yet, out of the other side of their mouth ...
Be advised that if your vehicle is covered by a warranty, you should follow the vehicle’s oil life sensor or the oil change interval recommended in your owner’s manual to avoid a disruption in your vehicle warranty. Follow your owner’s manual if the vehicle is operated in any of the following severe services: racing or commercial applications including taxis, limousines, etc.; frequent towing or hauling; extremely dusty or dirty conditions; or under excessive idling conditions.
Here it would seem to say that if you want warranty coverage, you must OCI with the OEM OCI (be it a fixed mileage, OLM, etc).
But you have to read VERY carefully; what they are REALLY saying is this:
In the first quote I put up, they are defining what MOBIL will cover, and under what conditions.
In the second quote, they are defining what the OEM will warrant.
There is a BIG distinction between the two. If you want the Mobil EP warranty to cover your engine, then you can run up to the OLM or 15k miles, whichever is longer. If you want the OEM warranty to cover your engine, you must OCI within the OEM guidelines. Simply put:
Mobil warranty = 15k mi or OLM, whichever is longer
OEM warranty = OEM OLM conditions
THAT difference is what they are defining.
And frankly, that is no different in concept than others such as Amsoil. Amsoil has a well written warranty were they will cover up to 3x the OEM OCI. The OEM won't cover that, but Amsoil will, if you follow all their conditions. Mobil is just doing the same thing, and clearly stating it. They do this because some folks might expect the OEM to warrant a piece of equipment where the OCI was greatly extended. The OEM has no obligation to do so. So the warranty burden falls upon the lubricant maker, not the car maker. Mobil is simply explaining the difference between the two. And you must OCI that load in a year or less for Mobil's warranty to apply.
So, as to the topic of the coverage for this UOA, Mobil 1 EP clearly states that this oil should be good for 15k miles, or longer. 15k miles is both a minimum and a maximum, situationally dependent. If your OLM maxes out before 15k miles, the Mobil is good past the OLM up to 15k miles; here the Mobil 15k is both a minimum assuance of performance and a maximum limit on warranty. But if you reach 15k miles before the OLM, then Mobil will warrant their product up to the OLM; here the 15k miles is a minimum assurance with an OLM max. (All predicated upon max 12 months).
And if you really want to nit-pick the details, Mobil would defer to the GM warranty up to the OLM, and then only cover issues once PAST the OLM. Get it? If you had a failure with 10% OLM left, regarless of mileage, Mobil is going to push GM to warrant; it's their OLM limit, after all. If the OCI went PAST the OLM, but under the 15k miles, then Mobil would warrant that bit between OLM and 15k miles.
As to the TBN, it's a bit low. Could be typical for this oil, could be a fluke. Another UOA or two would tell the truth. It does look at bit sketchy below 2, but more info would be good. Also, TBN is really only a big concern if acids are a big concern. Without a TAN, it's only implied and not a true "known". In the absence of acid, the low TBN would not be a big deal in and of itself. While inversely related, they are not inversely a guarantee of presence. Perhaps Mobil has statistical evidence to show TBN that low isn't going to adversely affect wear in the last 25% of an OCI? I don't know; just speculation.
If I understood Oneill5491 correctly, he inferred that the OLM hit zero, as his statement was he'd "do another UOA when the OLM gets to 0% again". That would indicate to me he OCI'd this time at 0% with a UOA. He reloaded his sump with more M1EP and same type filter, and will UOA again at 0%.
Practically, he is good past that OLM up to 15k miles for MOBIL warranty coverage in a year's time. He is covered up to the OLM by GM, then Mobil up to 15k miles.
