[Old Man Morris]

We have a 2006 XC90 with similar issues - high oil consumption, no sign of oil leaks on floor, no smoke from exhaust, soot filter full warning comes on as soon as driving over 2500 revs.

Smoke comes out of dipstick when removed, no vacuum at the oil filler cap when tested with a latex glove (glove fills with smoke).

Soot filter message goes away once car has been sat for a while, no need to try to regen.

We had the dpf cleaned, new dpf sensor, garage can't figure it out.

I bought a PCV valve online and asked garage to fit it but they stopped as they couldn't extract rear bolt and didn't want to risk snapping it without having other housing available.

Any tips on removing that bolt?

I also read that in many cases swapping the PCV valve has no real impact.

I took the diaphragm out of the new valve and swapped it with the old one. The old one was a bit wrinkled but still looked intact and no holes or tears. But no difference in performance.

Is it possible that the PCV housing can fail so the whole thing needs replacing or if the diaphragm is good does that rule out PCV failure?

Does the whole of the PCV system (including hoses) need changing to be sure?

Some people mentioned changing the oil separator cartridge, any feedback on that as a solution?

Lots of questions but we'd be happy with any tips as we're so close to scrapping the car but would hate to do so...it's putting us off going for another volvo but we love the car!