Something thats been bothering me for a while this, i've had the tank off on my escort a couple of times because of various problems with the fuel pump and it's coming off again this saturday as it is hissing a little bit when the pump first comes on to pressurize the fuel system. I'm just wondering what exactly the small round thing is for near the top of the filler pipe, it has a small tube running from it which attaches to the top of the fuel tank. Is it simply to catch drips when you're filling up or does it have a more important role?
Also, anyone got any idea's what could be hissing? The car has been an absolute pig to start recently especially when the engine is warm and has been left standing for a bit, fuel usage doesn't seem any worse than normal although i have alwasy been getting the smell of petrol wafting in now and again ever since i got the car but i've never been able to find a leak.
Suggestions?