Intake tube of under watered

Moin Fahre currently has a V70 D5 from 2002. But I intend to switch to the new model in the foreseeable future. I posted this post already in the V70 II forum, but unfortunately I didn’t get any feedback yet. Maybe I’m more lucky here. So I looked at a V70 III with D5 engine a few days ago. Actually the engine is nice dry. But… the intake tube is very smeared from below. I’m not sure if the oil or diesel is. The pipe comes from the air filter (gear transmission). From the bottom, a perhaps 3-4cm thick tube goes to the intake pipe (just before the intake pipe goes to the rear (crank housing ventilation?)). I think that the dirt comes from this area. Does anyone have any idea what problem the engine might have, possibly worn out piston rings or weak spot seal? I know, is a little like coffee set lehserei. But maybe it is also a well-known pro blem. Would I be very pleased about friendly information. LG Ralph Oh yes, does someone have the opportunity to get something out about the car using the VIN?