Guys, I will openly profess to knowing almost zero about the 6.4's. With that said, I have been doing some reading and research on them as I have considered strongly buying one. I also read the aforementioned post on PSN. It doesn't look to me to be that far-fetched of an idea to have and injector hang open or nozzle problems that could put enough fuel into the cylinder to hydro lock it. I know with the 7.3's that if you pull an injector, you should pull the glow plug and roll it over a few times to get the liquid out to ensure you don't hydro-lock it.
On another note, I was at one of our local dealerships yesterday and talked to their diesel expert about what kind of problems he was seeing with the new 6.4's. He said something that was interesting to me. He told me that he had recently had to replace the entire fuel system on a truck that the owner had filled with gasoline
to the tune of $8k worth of repair bill. Ford did not pay as this was caused by the owner. He did say that the owners insurance company did bail him out. I'll bow out now, and continue to watch and learn.