A vote for bypass filters. I've been running a Frantz bypass on my '95 Dodge Cummins for the past 20 years. When I first installed it the oil has a few thousand miles and had the normal black diesel color. After several hundred miles the new filter had removed enough soot that the oil was a brown color and eventual cleared up to the point it looked like it was in a gas burner. To this day, with a couple hundred thousand more miles on the engine the oil never looks like your typical diesel truck oil no matter how many miles on a change.
I used to send samples off and have the oil analysed by John Deere Labs. Samples always came back good to continue running the tested oil, so a few years ago I decided to go till the analysis said change. At 23,000 miles and over a year I gave in and changed it. The 23k mile oil sample came back good to continue running though. My policy since then has been to change once a year regardless of the miles.
Not exactly what the OP asked about but I do feel by-pass filters are worth the effort. I change the one on my 216 every other oil change since I only put about 5k per year on the truck and change oil once a year,. I doubt it's even close to capacity at 10,000 miles.
RonR
