I have been told by the dealer that the engine has a 7yr 100K warranty (extended due to problems) with their diesels. I have a 220d SEL and have been told to keep an eye on oil consumption, fuel consumption, warning light, coolant level and any changes to how it responds (sluggish or not). The re-build is costly and time comsuming. Expect your car to be away for a week.
Mine is a 2006, 220D SEL