If anyone can help, it will be much appreciated!

 

Filled tank as usual until pump cut out.  Then noticed patch of diesel at home on garage floor, underneath tank.

 

Garage removed wheel arch liners to check for leak, none visible.  Then replaced seal to pump/sender unit - old seal not in a good state.

 

Problem solved - until I filled up again.  Then patch on garage floor returned.  Have owned car since early 2008, now on 45,000 miles, first real problem we've had!  Only work carried out in vicinity was 2 years ago - rear o/s bush cut out and offside rear lower arm replaced.

 

Any suggestions welcome - thanks.

On a previous car of mine ( Peugeot 307 ) after owning it for 10 years it leaked out of the fuel tank if I filled it up to the brim.

As I always filled the car brim to brim to check fuel consumption this was a problem to me.

On top of the fuel tank there is a breather hole that should let the air out when filling, but close when the fuel/liquid reached it.

This had stopped working properly and would not close when the fuel got to the top of the fuel tank when filling and then leaked.

I fixed this by attaching a rubber pipe to the breather hole and led this pipe away from the fuel tank and up over the fuel filler cap.

After it looped over the filler cap I just let it hang down, this was all done behind the wheel arch liners.

The breather hole then could still breath but would not leak because the pipe was higher than the filler cap.

The breather hole was a device with many internal parts that you could only see by cutting/breaking the fuel tank appart.

The leak never happened again.

Hope this helps

 

Thanks AG Faclo

Many thanks for this helpful info, will suggest this at the garage when they try again to solve the problem..

My car has had two new tanks now as a mouse took a liking to the plastic for some reason. Apparently it is a nice warm place to sit on top of and make a nest due to the warm fuel that's returned to the tank. The second tank was made less comfortable for the mouse.

This thread covers it well

http://www.briskoda.net/forums/topic/343542-diesel-leak-when-filling-car/?fromsearch=1

Edited 16 August, 20169 yr by andy-fisher

Many thanks for the info and the link.  Intend to try not fully filling the tank next time (we only need a tank a month!) and if no leaks, will have further info to pass on to the garage.  The mouse theory looks promising and presumably the tank removal isn't too much hassle as long as it's pretty empty - note Haynes reckons it a 3-spanner job, i.e. Fairly Difficult.