Originally Posted By: sshimp
So, I have been hearing a lot of weird stuff about changes in Mercedes specs. First, I was told by a tech at a Merc dealership that he received and MB bulletin saying they should only use an oil that meets 229.52 on diesels because of emission system problems using the 229.51 approved oils, specifically Mobil 1 ESP formula M. I cant find a US market oil that meets the 229.52. Then I hear from a oil swap shop owner that he received a bulletin from Merc that he should only use the Mobil 1 0W-40 in Merc Diesels. Anyone got good info, not the boxed answers from Mobil/Castrol/Valvoline websites?
Well, all I can contribute to this is that the MB 229.51 diesel spec is satisfied by mid-SAPS oils, whereas the VW group's diesel oils (for example) are all low-SAPS now (504/507 and Porsche C30).
Just in case you don't know, SAPS is sulphated ash and phosphorus, both of which are normally found in motor oils for various positive reasons but have been found to prematurely clog up DPF's in modern diesels.
So, I don't know this for sure, but maybe the MB 229.52 spec is now strictly a low-SAPS spec??? That is really the info you'd need to find out from someone, because that would give you a possible answer or direction to go in.
However, if you want to take some preventative action right now but still be totally compliant with MB specifications, you can use Mobil 1 ESP 5W30. It is a low-SAPS oil, but it is still approved to MB 229.51 spec that your car required when it was purchased.
The oil that the dealers currently use (M1 ESP Formula M 5W40) is also 229.51 approved, but it has a mid-SAPS level of additive.
Hope that helps a bit.