I have heard of turbo issues as well as raditior issues...the motor didn't last long in the Ford Truck line.
I never heard of the turbo issues but then again I haven't been hanging around the Powerstroke forums much anymore. If Im not mistaken the radiator issue has something to do with the plastic/composite end caps can crack and cause leaks.
The reason the 6.4 didn't last long is because it was pretty much a temporary fix between Ford and Navistar after the 6.0 disaster. The 6.4 was pretty much a bandaid until Ford could get their own in-house build engines developed and in trucks.
Sadly with all this emisions crap I doubt we ever see diesels that will live up to the durability and longevity of the 7.3 Powerstroke and 5.9 Cummins.