gwengler wrote:

D-ECAY, a C172R, has a Thielert Diesel installed. A detailed
"Dauertest" kann be found at www.pilotundflugzeug.de I don't think
Flight Training Cologne, the operator, is happy with the performance
for various reasons, mainly engine un-reliability,

You didn't read carefully enough. The enginge has proved to be very
reliable, not a singel engine out or other sudden anomly has been reported.

However, they did have problems. This seems to be mainly a problem with
integrating the engine into this particular Cessna model: Power
reduction caused by the muffler and the like. Certainly not what you
would expect, but not a problem of the engine as such. I'm not aware of
similiar problems with the DA40.

Stefan