woosh when opening fuel cap

[brens-e200]

hi

I noticed that when i release the petrol cap there is a loud woosh sound as if there is an in rush of air. Never had this on any other make of car and was wondering if this is normal for a 1999 e240 ?

thanks in advance

brendan

 

[mr. shr]

I used to get this on my W220. But not on anything else.

I just put it down to the fact that my S-Class was a thirsty beast so needed to burp before each refill.

 

[rpneed]

I'm pretty sure all fuel tanks have breather to prevent this from happening. If there is a breather and it is blocked in can cause fuel problems. It is usually part of the filler cap.

 

[andy clark]

your fuel system is pressurising you must have a blocked vent

 

[welland99]

your fuel system is pressurising you must have a blocked vent

or vacuuming?

 

[EDZ649]

This happens in both my cars and previous ones, nothing to worry about.

 

[trapperjohn]

Happens on all my 124s. Rest easy mate.

 

[brucemillar]

It's the sound of money being sucked out of your wallet.

 

[Danny DeVito]

my car does it when the fuel i really low, or should i say mine does it all the time

 

[cl55 amg]

mine always does it..

 

[300CE]

Happens on my 300CE too, although i'm still getting a 'dong' every now and again from the tank so will be changing the charcoal filter in the near future.

 

[Stratman]

Many years ago I had a Daimler 2.5L V8 (MkII Jag shape). It ran nicely except when I booted it at motorway speeds. It then misfired badly, losing power. Plugs, points, dizzy cap and the rest had no effect. I pulled into a motorway services one day for petrol and when I took the filler cap off not only was there a giant sucking sound but I heard the tank unbuckling as well!

The bottom of the tank vent tube was plugged with mud, and the SU electric fuel pumps carried on regardless, creating a nice vacuum in the tank. A quick prod with a screwdriver cleared out the vent and increased the top speed considerably.

 

[trapperjohn]

Happens on my 300CE too, although i'm still getting a 'dong' every now and again from the tank so will be changing the charcoal filter in the near future.

Not got a pussy in your well have you?

 

[300CE]

Not got a pussy in your well have you?

Haha!

 

[Gucci]

Happened on my W202 and W163 - never occurred to me it was an issue. The fire brigade weren't so convinced at either of their tank fires.

 

[samthesidecar]

Weather's warmed up, tank pressurising, does the breather have a one way valve to prevent spillage?

 

[Danny DeVito]

I looked at my cap yesterday and the inside looks all rusty and the holes underneath are smaller than they should be. Whats anyone else's like ?