MK3 fuel tank breather valve

[Arnoldhar]

Guys, does anyone happen to have a spare non return breather valve for a non injection tank, i think mine is letting by as the fuel keeps draining back to the tank when the car is standing for a few days

thanks

[Major_Tom]

Do they have non return valves in them? I think mine is just a hose. If mine is standing for a few days / maybe a week, the fuel filter is nearly empty. I assumed this was normal and the car's way of accusing you of not driving it enough.

[stevemarl]

The breather valve is just that, it allows air into the tank to replace the fuel leaving it, preventing a partial vacuum. It`s one way so air can get IN but fumes can`t get out; there`s no `non-return` valve sas such in the system (apart from the valves in the pump but they`re not 100%)
Seems to be worse with unleaded than it used to be with `proper` leaded, more volatile, my float empties/evaporates in a couple of warm days which it never used to.