This is why. Taken by me, today from BMWUSA's website. These are the only "approved" oils on BMW's list if you chose to get something other that BMW Castrol 5W-30. They still use LL-01 as the standard whether or not you think it is outdated.


BMW Long-life rating LL-01 Approved Synthetic Oils for the US Market:

• Castrol Syntec European Formula SAE 0W-30
• Mobil 1 SAE 0W-40
• Pennzoil Platinum European Formula Ultra SAE 5W-30
• Valvoline SynPower SAE 5W-30

All are good oils. I choose to use Castrol 0W-30 (GC) because it is easier for me to obtain (Autozone) than going to the dealer. It is arguably a superior oil and I can get it on sale for around $5.00/qt. It is also more compatible due to similar chemistry/composition to the BMW 5W-30 which will be put in by the dealer. I change my own oil every 5K, some choose 7.5K miles, but since my X5 is CPO it will occasionally get dealer oil. I do feel there is a benefit to consistency in oil selection and not hopping from brand to brand with different additive pkg's etc. BMW 5W-30 is fine, just a personal decision on my part to use the 0W-30. It (GC) gets rave reviews on BITOG and I drank the koolaid! I have used Mobil 1 0W-40 for years in my AUDI's with great results. It is good oil and would be my 2nd choice. PP also gets rave reviews on BITOG, though I have never used it. I don't think you can go wrong with any of the choices especially if you cut the OCI in at least half.