Fuel Vent Golf V

Hello everyone.

I've had a Golf 5 GTI since the end of May (engine code: AXX, transmission code: GVT).
After a few days, I noticed some noises coming from the fuel tank while the vehicle was stationary, but I didn't investigate them further.
Currently, it seems that when the outside temperature reaches approximately 27°C, the fuel tank is either not ventilated or not adequately ventilated during refueling.
After about 10 km of driving, the bottom of the fuel tank starts to lift slightly. After 25 km, there's already a 5 mm gap between the retaining strap and the bottom of the tank, and after 50 km, the gap is over 1 cm.

My friendly VW dealer has already replaced several parts (including the activated carbon filter, fuel cap, and a ventilation valve), but the problem still persists.

"Does anyone else experience this problem? The demo car at my dealership has the same issue, although it seems to be specific to the GTI model..."


I would really appreciate any tips you can offer.


THX u. CU

CB.