Before doing anything further I suggest checking for engine codes.

A stethoscope that can be purchased at local auto is very helpful finding the source of noise. Sometimes it is easier to use a long extension for a ratchet--the solid end on the engine and the slotted end to your ear.

A ticking noise is seldom from something driven by the belts, especially when it goes away at higher RPMs.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas