After a run there is petrol around the filler cap as if it has spilled out during cornering.I've tried different petrol caps but its still there.Also when I release the cap there is a "whoosh" which tends to indicate the cap is not leaking as its holding air pressure.Any ideas?

Are you sure it is petrol? Could it not be something else? Just making sure.

 

Do you get the hiss sound virtually every time you open the cap?

 

How much fuel on average do you have in the car? I personally fuel coming out the cap if it is full.

 

Maybe fuel is reaching the cap and it is designed to let the fuel come out of there.

Mine did the same untill i put a standard filler cap on, some egit installed an aftermarket one that didnt seal properly

After a run there is petrol around the filler cap as if it has spilled out during cornering.I've tried different petrol caps but its still there.Also when I release the cap there is a "whoosh" which tends to indicate the cap is not leaking as its holding air pressure.Any ideas?

 

i always get this noise when taking off petrol cap, just thought it was due to the fuel system running at high pressure :confused:

The hiss is normal on most cars.

 

The Z has a fairly common problem with the filler neck rusting and petrol leaking out but i'm not sure you'd still get the hiss if that was the case.

Have a look/feel up under the arch to see if you can find any holes/rust.