I have Sprinter 313 registered Jan 2008
The engine was replaced at 260.000 miles, and now it is on 500.000 miles !
It is serviced regularly by my local mercedes dealer.
For the past year it has been "gaining" oil ? the level rises on it's own, the drivers all insist they are not putting oil in the van, i do have another 2008 van that was doing the same, but now seems to have stopped mercedes have taken Oil samples and tested, but say it is fine, No water / Diesel getting into the oil.

To add to this problem, the van is now smoking badly, but ONLY after having done a long run ? There is NO loss of power, no warning lights, and in general it drives perfectly.
the vehicles spend 95% of their lives on the motorway at 70mph, so as far as i understand, the DPF should not be getting blocked, But mercedes have said they think this is the problem.
the smoke is white and permeates thoughout the vehicle making driving very unpleasant.
I have spoken to several other mechanics and had conflicting theories including EGR valve, DPF, Leaking injectors ETC ETC ETC, But NOBODY seems to be able to diagnose the problem definatively.
Does anyone have any insight into this ?