Wow, a lot has happened here overnight. Do any of you guys sleep?
@ToyotaWill, Couple of things here. I found the sludge at 45k miles. I don’t know why I didn’t notice it earlier. There is still some contamination of oil from combustion by-products. Todays engines burn gas so efficiently that the combustion by-products have been greatly reduced.
I am not using drive cycles to determine oil changes, that would be too hard to track. The oil change monitors that many cars have use drive cycles as one of the factors they monitor. They monitor other factors as well. But for them to be accurate, you have to use the oil that meets the specs that the monitor was programmed with. The monitor cannot actually analyze your oil either for use or type.
The Moss-Magnusson Act tell manufacturers that they cannot specify that you have to use only their brand of oil or that it has to be changed at a dealership only. It does allow them to establish specifications for the oil. If you chose to use an oil that does not meet the specifications and you have an engine failure, then they must prove that the failure was caused by the oil. For example, they could not blame the oil for a broken valve spring. They still might not cover the engine if they can prove you over-reved it but they can’t blame the oil.
Beyond that, I am not going to get into the discussion of the merits of one oil over another. Your car, your money, not my business. I don’t even care how often you change your oil, I was only reporting an experience that I had. That is one data point out of millions of data points. It is not a trend or a graph or a proof of concept.