Now that I'm stuck doing all the ^%$# work to get JAA papers , I drive a Taxi on the weekends to have (and save) some money. I work for an comapny that has Diesel Mercedes and some of them have as much as 700.000Km/+- 434.960Sm http://www.pprune.org/ubb/NonCGI/eek.gif ,the car don't look too good anymore from outside , but the engine runs fine!
As for the aeronautical Diesel engine , my A&P instructor talks about the Renault engine that is doing the tests ,designed they say by the F-1 engineering team. He also says that both Lycoming and Continental are working on them too(even if not known by most of people) mostly because something related to the future of AVGAS - something to do with an already defined date to be put aside by the Oil company's in a not very distant furture. (At least is that that I've been hearing lately - don't jump on me because of this statement as it can just be a rumour).

My last 2.5 litre diesel Merc did 220,000 miles without so much as a cough! The second owner still hasn't spent any money on the engine. My current one seems good so far and with 178 BHP from a 3 litre diesel turbo, that ain't bad!! I also hear that diesel engines run on tractor fuel so farm strip costs should be really low!!