Petrol smell

[Weldfixfab]

Hi all again heres on for the brains among you ive a cls 55 amg took her out for a blast on a nice sunny day i had been driving about 3 hrs or so and started to notice the smell of petrol .. it seem to be going from the rear of the car but since that time i can not smell a thing .
Any ideas ????

 

[optimusprime]

You will get fumes from time to time the tank has a small breather vent .