Fuel Leak

[Morat]

I went to start the car today and found a nasty patch of fuel stained road underneath the rear of the car. I'd brimmed the tank yesterday (5miles from home) and parked it with the nose facing uphill. I don't know if the much warmer weather today made a difference but there was a 3ftx4ft patch of damp tarmac

I'm guessing this is the filler neck - does that effectively mean a new tank?
This is a real pain, especially as I had new rear subframe bushes 18 months ago :/

There's no chance that this is some form of breather/overflow arrangement doing its job is there?

[sweep]

The neck is seperate from the tank,but sometimes they leak around the metal short pipe that is part of the tank,the rubber filler neck pipe fits to this part.i have two good tourer tanks if needed +a filler neck.(sheffield)

[Morat]

Thanks sweep!
I'll try and get it up on a lift on Monday and see what is going on. I may well be bothering you for a tank if its bad news....

[fuzzy]

its most likely the small piece of stub pipe welded to the tank that the rubber hose attaches to that corroded meaning a new tank, the next common cause is the metal section of filler neck corroding and thats about £150 new from bmw iirc. if your really lucky it could be the rubber hose thats spilt but ive never had that problem yet.

[Simon13]

if you have brimmed it, i expect its rusted out around the seam. The tank is 2 piece as such and joined at the top. I had this in the past you could get a away with 50 litres max.

If it was the filler pipe or the stub on the tank you can only get away with 20 litres odd.

Probabaly time for a new tank!

[Morat]

Damn, it looks in really good condition from the underneath!!

[Brianmoooore]

O ring for the fuel pump is another prime suspect, is easy to check, and the easiest to repair.