Don't know what engine, but I've been googling since I posted, and premature sludging appears to be a serious problem with Chylser engine designs recently.
Probably due to the tiny oil capacity (imagine, a big V8 with a 4 quart pan!).
I only see the kid on weekends, will have to try to get in contact earlier, he's been ripped off twice -- paid way too much for the truck in teh first place (cheapest vechicle to make is a pickup), and then when the engine fails due to design failuire, they stick him for repairs.
I guess we are supposed to buy a new vehicle every couple years, eh, then dumpster the old one before it's paid for.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!