Thank you for your long reply :-) Okey, I hear you! I have been driven diesels for 35 years and a happy DIY mechanic, not afraid of projects. My daily driver is a Subaru XV 2012 diesel. Seldom rev it above 3000 rpm, and no problem with smoke or performance. But I do some full pulls now and then, so that might support your theory. Also have an Oldmobile 1982 350 v8 diesel, but that one never get a full pull, and does not smoke.. Some more history on the Nissan. It´s the wifes dailydriver, so it has not been driven hard. Normally cruises down the highway at 70 miles/h. When we bought the car it had about 21000 miles on it and was 3 years old. Does not touch the oil at all. I rarly fill in oil in between the services. Smoke from both oilfillercap and dipstick. I´m absolutley certain that this hasen´t been like this for mstart of ownership.. If your theory is correct, would you say that it´s to late to try an Italian service? Or let me put it like this, would you do it? I think I can organice a compression test, but the leakdown test will take some work as I don´t have the correct tools for the job. What bothers me is that the car has good performace and runs just fine... I appreciate your time! All the best