Hi
I have only had my 2012 A4 Avant a court of weeks, I had a removable towbar fitted a few days after I bought it, then I noticed a clunking noise from the rear of the car, sounds like to boot isn't shut properly but it is.
I have searched all over and cannot find where it is coming from, I can't be sure it has been caused by having the towbat fitted due to only having the car a few days before it was fitted.
It only happens on a bumpy road and sometimes it's worse than than other times, maybe opening and closing the boot is having an effect on it.
Any ideas?
It's not loose tools or the side panels as I have removed them all whilst looking for the noise.
Thanks

 

Make sure your tow bar bolts are tight and then check for any cleance issues. Since the tow bar is new you might see scratches or rub marks on it is any part of the car is making contact with it. You could also lay under the car and have someone "bounce" the rear of the car while you see if you can locate the noise.