One problem related to engine belts and pulleys has been reported for the 2004 BMW 745. The most recently reported issues are listed below.
Coolant transfer pipe seal is made of improper material that is not compatble with high engine temperatures. Seal fails causing loss of engine coolant. Seal fails at 40,000 to 110,000 miles. Repair is approximately $6,000 because engine must be taken apart to replace the seal. My seal failed at 104,000 miles. Loss of power steering and vehicle stability control due to coolant leak onto serpentine belt.