BMW vehicles produced up to 10-28-2010 (including 7-Series F01, F02, F07), F04 ActiveHybrid 7 F04 and 5-Series F10) may experience a pulsing or droning noise heard from the front of the vehicle.
The likely cause: The auxiliary water pump or the water hoses that lead from it may be in contact with the adjacent components, or the auxiliary water pump may be installed incorrectly on the rubber mount. Harmonic vibration from the auxiliary water pump is being transferred through pump mounting bracket.
Remove the auxiliary water pump (follow repair instruction REP 64 11 262/removing and installing/replacing auxiliary water pump), and remove the original water pump bracket. Install the new water pump equipped with a supplied modified bracket. When reinstalling the pump, ensure that the connecting hoses do not come into contact with adjacent components.
The replacement auxiliary water pump is available under part number 64 11 9 253 081.