White smoke in return to carter

Hello, I tell you a problem that has emerged to a colleague in your van. It is an Opel Vivaro, from 2003, and suddenly, without any symptomatology or anything weird, it has begun to make a white smoke due to the return of the oil to the carter. This tube is next to the oil filling plug, on the rocker lid, and ends in the carter. For when the van is burning smoke by that tube, it is white and does not smell much to burned oil or anything. As soon as the van goes out the smoke disappears immediately. The van works perfectly, and the oil is not sorry with water or anything, it has a normal appearance. Well, if anyone knows what can be happening, I would appreciate a help, thank you

So you comment on the white smoke we could say that it is water but you say that the oil is not emulsified, what could be happening is that the butt had a small fissure which does not allow a great passage of water but if in the amount to produce the evaporation of this and go out through that place I would prove to the clutch to discard fissures.