It will be the breather pipe that has been cut away due to the poor design which is causing the deisel to leak when you fill the tank fully.
You won't be able to fix this yourself by putting in a smaller pipe inside as the breather pipe is connected at both ends, one to the tank and the other to the filler neck. Putting in a pipe inside the breather pipe will not give you the seal at both ends and deisel will still leak when you fully fill the tank.
Look at my photos on the very first post for the exact problem.
Unfortunatley you are just another case of this issue and I would advise you get in touch with BMW UK, argue your point and get them to pay towards the repair and also get in touch with VOSA and file a defect report. By now VOSA must have many complaints so they must have to react to this.
Originally Posted by strugers1
Hi i have just found the exact problem on my 55 plate 330d....had the car a week and i brimmed it yest and made sure it was as full is full and a small leak on my driveway..but now i have covered 60 mile no leak...so it mist be.the over flow pipe thing
the top end of the over flow pipe,how does it connect up?because i am thinking of putting a smaller bot of pipe down into the overflow pupe to save.the stupid costs of getting it.repaired....
Many thanks karl