[jzchen]

Originally Posted by pepsih

can someone explain me something.
On BMW official website mobil 5w30 is not in the recommended list

http://www.bmwusa.com/Standard/Conte...ngineOils.aspx

"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"

why???

the user manual recommend castrol oil 5w30 but that oil is not an LL01
http://www.castrol.com/liveassets/bp..._Sept_2011.pdf

So which one should I use?

I thought I could just go to the Mobil 1 website and find the TBN number for Mobil 1 5w-30 for you, but it is not listed there, (I think it used to be.) I think I saw it before as less than 10. The higher the number, the longer the oil is supposed to last. It resists acidity from combustion byproducts. From my "research" 10 and higher qualify. If you look at the Product Data Sheet for 0w-40 it is 11.8, which is very high... I'm still sticking with BMW 5w-30. Found it at a local dealer for ~$7.50 and allowed my BMW car club card to get 10% discount.