2. Check the accessory drive belt for damage. If any chunks are found to be missing, install a new accessory drive belt. REFER to: Accessory Drive Belt (303-05C Accessory Drive - 5.0L 32V Ti-VCT/5.0L Ti-VCT V8 (308kW/418PS), Removal and Installation).
Pilling
Pilling is dust that forms in between the ribs of the accessory drive belt from rubber that is worn off the accessory drive belt when it is new. There may also be loose particles left on the accessory drive belt during the manufacturing process. These are worn off and form into small balls of rubber that then get trapped in the grooves of the accessory drive belt. This condition will usually clear itself within 4800 km - 8000 km (3000 miles - 5000 miles) of normal driving.
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.