Clarify
One friend has a 2005 where the #1 cylinder has lost most of it's compression. The dealer is telling him that his #1 cylinder is making about 25% power from where it should be at. I think they somehow determine this based on some scan the there "Star tool". He is planning to auction off his truck as is.
My other buddy had a 2008 CTD and an issue with his truck where he punched a hole through the side of the block. This engine was under warranty and replaced by the dealer. The dealer suspects, based on their expertise, that one of the cylinders experienced "Hydraulic Lock", while he was starting the truck. The hydraulic lock would be the result of a leaking injector.
hearing about both these issues makes me think that the older style diesels (Non-Common rail) even though less powerful are a little more robust, as an injector failure should cause catastrophic damage.