Owners of 2003-05 F-Super Duty pickups and Excursions and 2004-05 E-series vans with 6.0-liter diesel engines may complain that their drive belt frays, shreds or breaks, usually more than once.
Ford says the problem is limited to trucks built before Jan. 1, 200, and is most likely due to a damaged or bent water pump pulley.
Installing a new-design pump pulley, part # 5C3Z-8509-A, should eliminate the condition immediately.