Yes, this test that Mobil ran is not showing the severe service of cold starts, stop and go wear and tear, which would put the oil's ability to protect against that kind of wear to the test. Cold starts and short trips would cause the oil to have to deal more fuel dilution as well. So, this is one type or form of severe service.
Another form of severe service would be high heat and high loads, which tests the thermal and oxidation stability of the oil.
I like the fact that Mobil ran the test and posted the results. They have confidence in their product. They know it is robust enough to handle extended drains. And high load conditions.
What other readily available oil that you can walk into almost every store and purchase is capable of being run for 25,000 miles? Castrol Edge (when it first came out) was saying it could be used for up to 15,000 miles (excluding severe service).
That's about the only one I can think of. When Ultra was first introduced, Pennzoil recommended 4 months or 4,000 miles for oil change intervals. Valvoline used to recommend changing their Synpower oil at 3 months or 3,000 miles. This was their full synthetic oil, and they didn't recommend extended drain intervals.
Mobil not only ran the oil to 25,000 miles, but it was run in third gear, and 1-2 quarts low on oil.
I would be curious if other oil makers ran this test, what the results would be? I don't think some of the other oils could make it to 25,000 miles fully topped off (the oil makers don't formulate and blend them for that). But, run them 1-2 quarts low and see what the results are.
Amsoil seems to be about the only other one willing to run torture tests on their oils and publish the results
