I for myself would think twice about flying with a SE diesel as much as with the DA42 twin diesel engine ( you may check the various incident/accident reports on that). It just takes an corrosive battery line or contact for the engines to quit, at least on the DA42, so forget about ME safety with fadec and so on on the DA42. Don't know though how it works on the 172 but it can't be much different. There have been problems with the diesel powered DA40 as well, again, it just takes anything abnormal in the electric circuits for the engine to quit service. It once happened with a DA40 that the FADEC initiated the emergency "program" for the engine which resulted with the max. power decreasing to 40% so you end up in a more or less controlled descend being unable to maintain altitude. Can anyone enlighten us about the construction / reliability of those thielert powered cessnas?

The Thielert engine has two limitations about fuel temperature: one for starting (-22F) and one to have it running.

What is important to know about Diesel engines is that about 30% of the fuel is not used in the engine and comes back to the tanks - and this is how you will keep it warm enough, even at FL100 !

If you fly the retrofitted C172 you will see that the "BOTH" position on the fuel selector is gone. The warm fuel goes back in the tank in use, so you will have to switch periodically to avoid fuel imbalance but also to keep both wings "warm".

On the good side, the engine management system will warn you if fuel temperature is too low.

More about it in http://www.plasticpilot.net/blog/200...e-like-it-hot/