When I fill up with fuel, there is often a loud hissing noise, as if you are opening a bottle of fizzy drink or something whenever I unscrew the petrol cap.
It also seems like there are vapours rising from the hole, as there is a shimmering shadow from the tank.
What is the cause of this?
Is this a problem?
Does this mean my fuel tank ventilation valve is broken?
I have a 2003 Opel Agila