Petrol filler cap whooshing

[JimSharp39]

All,

My 170 1997 230SLK fuel filler cap makes a whooshing noise (pressure being released) when it's unscrewed. Not sure if its due to low or high pressure in the tank. Should the cap have a vent to prevent this? The car's performance isnt affected as far as I can tell.

Many thanks in advance for your thoughts

Jim

 

[television]

Your car is normal as the tank is pressurised as all modern systems are

 

[jibcl500]

I have 4 Mercedes and they all do it.

jib

 

[JimSharp39]

whooshing

thanks for all the advice. Mind's at rest

thanks
Jim