You ALL Oil Gurus, here's a Question :
Since we have many highly knowledgable oil gurus here, I thought I'll ask 2 questions ~
1. I have seen many photos posted here of Mobil1 5-30W. Many people mentioned the Mobil1 5-30W also.... BUT it's not LL-01 approved. There's no LL-01 mentioned on it. The Mobil1 0-40W is LL-01 approved, however. So, why we have so many guys who encourage the "approved" BMW oil, say Mobil1 5-30W is a good choice? (It is however, Corvette recommended, so I guess good enough for BMW too, but not LL-01 mentioned)
2. I have put 0-20W (full synthetic) recently. I know it's not the right voscosity recommended. But I needed to change oil quickly, becuase the old oil was getting dirty. I intend to run this oil for only 2K miles or so. I figured this will also flush the engine, and will go back to 5-30W. Is that bad for the car? (by the way I'm getting better gas milage with it. Getting 23.5 MPG, before 21-22 mpg) I intend to go back to 5-30W, but now not sure if I should use the Mobil1 5-30W (full synthetic, since it's not LL-01 approved). Castrol 5-30W European is hard to find.
What are you views on the metioned concerns?!!! Thanks in advance!
Last edited by Newbie528; 10-08-2011 at 10:00 AM.