Fuel leak, tank pressure, empty, wallet, Suicide bomber?!

[dantheman6554]

Searched high and low for this on ehre and uk-mkivs,    1.8t, im runninf revo,  for the past few weeks, ive had pressure building in my fuel tank when i fill up, now its to the extent that even with the fuel cap not done up, when i fill up, it will throw fuel 4ft out the cap and across the forecourt,

When i drive it basically building pressure, the other day after a 20 mile drive to worcester i stopped in traffic for 10 mins creeping, it was leaving a trail of fuel while i was driving, and a large puddle when standing still,  after leaving it for an hour and putting fuel in it, it was fine on the way home.

last night was the worst, it started leaking, so i pulled in , left the engine running stupidly, which must have added to the pressure , so it leaked no less than 3.5 litres all over the floor!  , to which a bloke said to me are you trying to blow up the garage !?    , i wasnt in the mood so he had a short and simple answer  " piss off and mind your own business!"

So my thoughts are,  slit in the fuel pipes, ( but then why is pressure building) ,  purge canister?  , fuel rail?

Anyone got any thoughts


Dan

[Wayne]

I believe if you check you should somewhere on the tank a breather pipe, my guess is that it is blocked.

[jonnyturbo]

breather pipe runs in wheel arch of drivers side rear wheel hth

[dantheman6554]

Rear wheel and arch liner out then?    cheers guys will have a look tonight, tis costing me a fortune!

[nige_s]

Sounds like it's a breather pipe, the tank is pressurising and then forcing the fuel out at a week point.  I'm not 100% certain but some do have one way valves too.  A quick test, would be run without the filler cap fitted, or buy a spare one and drill a hole through it so it can vent.

The breather pipes will most likely run through a charcoal filter too so you can't smell the fuel.  You could just disconnect this and see if the problem resolves.

[dantheman6554]

Yeh thats how i notice it is the smell out the window, then you can see the fumes coming from the petrol cap, will have a look underneath tonight at the pipes and filter, have a spare one at home i think,   cheers guys

[nige_s]

Also you may find that it's not actually pressurising but the reverse the tank will compress under vacuum as fuel is being sucked out, when you pop the filler cap the rush of air entering the tank and it deforming back into shape displaces the fuel.

So it's a sucking action rather than an inflating action on the tank.

[andc1]

i had similar on my old pug 306, i drilled a hole in the filler cap, solved

[Andyfloss03]

just to add did this get solved...only mines like this but worse you can hear the tank re shaping when you pop the filler cap off....if you run it without the filler cap it just constantly pours out the filler neck and its only a 1/4 full?

p.s sorry for draggin up an old thread but its the only i found that relates exactly to mine....at the weekend ill try the breather although it was pi55in out of that earlier on when it got bad?


only thing thats happened that i can think of is the car ran out of fuel so could have picked crud out the tank???

[Wayne]

Check the breather.