what is it

[Geoff Wakem]

Hi

my car is  2014 335I Tourer and during recent trip to spain developed an annoying noise. Took a look underneath car this morning and discovered a small box ahead of the rear axle (when viewed from rear of car). it seems to be held in place by a single nut but with specialised head ie my spanners/sockets will not fit. It is very loose so I suspect that this is what is making the annoying noise

So, what the hell is it and should it be loosely mounted??

[Greydog]

Morning Geoff 

That is a vibration damper the bolt is an M8 Star socket screw the nut M14 and no it shouldn't be loose. One of my son's friends had this I used a Torx socket to remove the bolt the rubber mount seemed in good condition so we put some thread lock on and replaced it tightened it and two years on no issues (well he hasn't complained or mentioned it since).

Have a look at www.realoem.com it should show you what you are looking at 

Good Luck

Dave