My 2012 X5 had an intermittent noise/rattle/squeak that was driving me CRAZY! I think I found the fix and wanted to share it with you.
OK the sound was intermittent and seemed to come from the rear. Like maybe a seat beat was knocking or the tail gate was bouncing. I took it to the dealer who said.. if guessed you "we can't hear it" you're a winner!
So this is what I found....
I wanted to change the license plate frame and of course the cheap rear OEM plate holder had a problem. When I tried to remove the screws they stuck and then just started spinning. I ended up cutting them of because the nuts on the inside were loose.
While I was replacing the frame I noticed 4 tiny scratches where the 4 plate screws went through the frame. It looked like the screws were almost touching the body and had occasionally had started to scratch the paint! I'm guessing when I hit a bump the screws touched the body and made the ticking sound.
So I went to PepBoys, and got a universal plate holder for $5, and that seems to have fixed the noise, or at least for now.