this is more of a question from my father (he drives a 2003 X5), but here goes. crusing down the highway usually around 80 everyonce in a while there is a LOUD honking sound. its not the horn misfiring, you can tell from the inside the the air is catching something near the front left of the hood. its making something vibrate and for the life of us we cant find what it is. last resort was we took it to the mechanic, no luck he took it out and nothing! so we'll be driving along and people think were honking at them as we pass, its hilarious but its getting annoying.
any suggestions? ideas? :help