I’ve got an 87 S3 xj6. I have this rattle whenever I close the doors. It sounds like it’s coming from the fuel filler. I think both sides do it but not certain. The drivers side definitely does it but I think the passengers side does as well.


would anybody have any ideas what it might be?

 

The rattle is from under the rear parcel shelf and it is the sound of the air vent flaps being opened and closed by movement of air as you close your door. The movement of the flaps is what allows stale air to be removed from the cabin. The clanking noise occurs because the foam backing on the metal flaps has disintegrated.
The metal shroud in the trunk that covers those flaps can be removed (with some difficulty) to access the flaps and to refit foam pads to silence the noise.
This has absolutely nothing to do with the fuel fillers.

 

You could be hearing the infamous “cow bells”. Lots of archived info. Just search cow bells

Cheers
DD

 

After reading a few threads, I suspect you’re correct. I think my jag will simply continue to have a unique character as I don’t hear them anytime other than on closing the doors.

thanks

 

thank you for the quick and informational response.

 

to do a proper job of replacing the foam pads (or headliner fabric) glued to each rattling vent flap, the water Catch Pan should be removed from under the rear parcel shelf.

BUT: the biggest risk in doing so, is that the Sunroof Motor must be unbolted and the Sunroof Cables must be dislodged from the motor, and that requires removing the entire rear Seat. A massive job.

The trouble starts when re-engaging the Sunroof cables to the Sunroof motor Gear.
The cables will never go back to the same notches they were before removing them, AND it is easy to confuse which cable pulls and which cable pushes the Sunroof panel.

you can glue new pads to the metal flaps by pushing them in through the rectangular openings seen above the trunk Seal In the water channel, using thin tools, one to grab, one to pull the new pad, then pushing the new pad against the metal flap. Use 3M Headliner Adhesive (spray) on one side of each new pad.
This will eliminate the "cow bell" rattle.