the measurement of insolubles is important. Modern diesel oil like Mobil 1 TDT
have formulations that keep soot in suspension at higher levels. This makes insolubles not as big an issue as with standard dino oil. Thus one of several reasons allowing longer OCI. I believe the older diesels 240 and nonturbo 300D have higher soot production. When you combine Low sulfur fuel and
full synthetic diesel oil soot is really no longer much of a concern.

I will relate a recent disaster of a close friend. He drives an older Freight Liner
with a Cummins. It had 1.2 million on the original bottom end. He drove up to
the Canadian border in January. He had 20,000 miles on the oil. It dropped to -30 F that night. He idled his truck all night to keep from freezing. Apparently the oil hit a certain threshold of soot and he woke up with the bottom end knocking. He finished off one of main crank bearings. So the moral is beware of high mile diesel with extended OCI in arctic weather. Idle apparently creates more soot during combustion.

__________________
1990 350 SDL
Currently: 180,000 miles
Factory rebuilt bottom end rods, bearings and head gasket @ 75,000 in 1997