One problem related to engine cooling system has been reported for the 2006 Ford F-350. The most recently reported issues are listed below.
2006 Ford f350 6. 0l diesel pickup coolant heater return line not properly attached to firewall leading to coolant leakage and/or exhaust gas leakage. The cab heater coolant return line was supposed to be bolted in two places to the firewall to properly hold the coolant line in place. On my truck the two nuts that attach the line to the firewall were never installed at the factory - as evidenced by the factory paint never been scratched on the studs on the firewall. Without proper attaching of the line to the firewall the line then rests on top of the turbo exhaust pipe eventually wearing through one or both of the coolant line and exhaust pipe. My coolant line ruptured at 30,000 miles.