Well it does use a little bit of oil, but not much. (maybe 1L every 3000-4000 km)
The CCV has never been serviced.. but there is a fairly amount of oil in the intake system.
The engine does not have any oil leaks, for what i know of.
I just noticed that the smoke/blowby stops at higher RPM.
Is it possible that the "blowby" i am feeling, is coming from the vacuum pump? (i mean the pump is mounted to the camshaft, right beside the oil filler hole)
But if that is true, where is the smoke coming from?
The CCV system, with all of its pipeing is typically replaced around 170k kilometers or 100k miles, or so, as a service item. Sitting at 350k kilometers or 210 k miles, I'm surprised it is functioning at all. The CCV at idle, should place a slight vacuum on the system. I believe this is where your problem exists as your oil consumption would be higher if appreciable blowby exists. Sounds like you still have a very strong m57 that will continue to serve you well. My recommendation is change out the CCV system and enjoy your 525dt, with reduced oil consumption.
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