I was privileged enough to get some insight from a Benz mechanic who had worked on these old diesels since the 70s. He taught me a lot in my 20s when I was a young tech. He had a trick of running straight high grade non hydrated veggie oil through the fuel system bypassing the tank and would run the car for an hour or so at a time, change the oil, make sure the valves were adjusted correctly and do some hard driving and the blowby would come back virtually non existent.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k