Well I guess you failed to notice that I said, "I have used Mobil1 for years and have always changed my oil every 5,000 miles, never a sludge.
I have never believed in BMW's 15,000 mile oil change and when my car was new I changed it once myself between each 15k BMW change!" Hardly a "long drain interval", regardless they do make a 5w-30 "Extended Performance oil". You can read about it on their web site,
Mobil 1. Do you have any idea who makes BMW's oil, they do not! In the early 90's it was Mobil 1, than they contract with Castrol, so really what is "BMW" oil?
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