a class possible time bomb

[buster2]

Hi a good friend of mine has an a140 54 plate, last weekend whilst in the kitchen of his house he could smell petrol on further inspection he could see that the petrol was running from the fuel cap of the car, he removed the fuel cap and there was a rush of pressure but the fuel continued to run out he then used a twig to depress the flap in the fuel neck and there was another rush of pressure and then the flow of petrol stopped.
The petrol tank was half full the engine was not running and had not been started that day. Any one experienced anything like this as he has spoken to the local dealer who have dismissed him as some sort of lunatic.

 

[Dieselman]

It sounds like the breather might be blocked and some fuel had run down it, which was then pushed out as the pressure built up due to the ambient temperature warming up.

 

[buster2]

Thanks deiselman
if this is the fault could this be a one off or does the valve need to be replaced