These are the various specs in my handbook. I will do some research this week when I have some time but I am sure some of the thicker oils where SN, 5w40s, and I am sure they were also Bx rated oild.
I will double check.
Having only done 6k miles so far i have not done an oil change.
B1 is due in 52days or just over 9k miles. I think the service interval is 15k or 1 year.
What interested me is that Mercedes still advocate the use of what many US based consumers would consider a very thick oil.
Kia dealers in my experience use 5w30 (2 different dealers) but Kia actually recommend 5w20.
I have put in 5w20. It may be my imagination but I think the engine was slightly noisier.
Out of interest would you run a thicker oil in a Mercedes diesel engine?
I am thinking 5w40 or even 5w50.
My only consideration is engine and turbo longevity.
If I accept a contract I have been offered I will be doing 70/80k a year in the Merc almost all on Motorways (Highways) with a projected 3 or 4 year vehicle lifespan.