Hi guys, it’s about the problem of the “gammel operation”, as a Mercedes master calls it. It’s about Sprinter 906 311 with work platform construction, so the things with lifting arm and basket, where you stand inside to clean facades or to cut trees. These stages drive in the morning to the workstation and then run several hours a day in a slightly increased idle of about 900 min-1. From a mileage of about 60-80 tkm, these engines start to smoke, and less Idle, but after several hours of idle, if you then continue normally. And indeed, the smoke is so strong that people behind you can see nothing and think that the sprinter is burning. One has to bear in mind that one operating hour corresponds to about 30 km of drive, i.e. the sprinters have about 300 tkm on the tacho. The engine oil consumption is almost not measurable, very low between the oil changes annually, I take Aral 0W-40. My theory is now that the engine in the Idle running is “warm”, but the exhaust or DPF is rather “cold”. When Idle running a bit of oil or diesel always passes the valve shaft seals and piston rings and escapes unburned into the DPF and collects there. If you continue after a few hours Idle running, the DPF gets really warm after 1-2 km and burns this accumulated diesel. The result is very strong white smoke for about 2-3 minutes. In the photo you see an old Sprinter 903 in Idle running, like the Qualm a No comparison when driving after 1-2 km after long idle, you would not see the sprinter anymore, but unfortunately have no photo of it. An old MAN of us had these torments too, after changing the valve shaft seals the smoke was over. The Mercedes master says these engines are not made for the idle and thinks that this would do nothing. What do you think? I think the old seals are widened, hardened, there is a lot going on. Of course, the valve shafts can also go through. I wanted to start with the seals. VG, Andre