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Originally Posted by
vasillalov
Mobil1 0W-40 is oil that I've tried throughout the years on many cars. I've done extensive and prolonged oil analysis over the course of several years. My conclusions are such that Mobil1 0W-40 is not a good oil for anything longer than 3000 mile oil drain interval. Reasons: it gets beaten down way too quickly, so it becomes more like 0W-30 too soon and it drops its TBN too quickly as well. Furthermore, Mobil1 0W-40 is NOT a pure Group 4 synthetic oil.
I would recommend Valvoline SynPower 5W-40 HST (not MST) if you can find it at a good price. It's pure Group 4, has an higher TBN than Mobil1 and it lasts longer.
I remember a post from you pertaining to this some time ago, so I did a little research and concluded that your analysis may have been off. I think it had to do with starting versus measured TBN value. Higher TBN is NOT necessarily better, but keeping a high ratio relative to starting point is. I believe Mobile 1 starts with a lower value so comparing just the measurements between different oils would not be an accurate assessment. Anyway, I don't remember all the specifics. At the time I was considering a different oil, but decided to stick with Mobile 1 0-40. "
