I recommend you contact MBUSA and smart's customer assistance center with your concern, rather than here.Well. I don't usually get upset or worried if someone says they don't use the correct spec oil, and they change their oil frequently, or even when one says that they still follow the long interval and their engine is fine. In this case Mercedes has accidentally contradicted itself and should give owners a definitive answer. Kamaal, do you know what the engine designation is? Is it not M 281? And the BEVO sheet says not 229.51....
I think I'm not being clear.
It is my understanding that 229.51 oils are specifically for diesels with diesel particulate filters, and not correct in a gas engine for 10k miles/1 yr. The TBN on the ubiquitous Mobil 1 0W-40, before all the revisions to the 229.5 list, is 12.6, vs 7.6 on the 0W-30 ESP.
I was shocked to read that the manual says 229.51, and am expressing concern. If you see the list with all the engines of Mercedes and associated brands, you'll note that if one engine says 229.5, it does not also say 229.51, and vice versa. Either the manual is mistaken, or the list on BEVO for the M 281.