Whoosh from fuel filler
 

Never gave it a thought because I thought it was normal to hear a whoosh when the fuel filler cap is opened even to the first detent, given that the fuel system operates under pressure. Then read a post in another MB forum where the owner mentioned hearing such a noise for the very first time on his SL500. Does the whoosh suggest I've got an evaporative emissions problem on my W124, or is typical to get a pressure release after the vehicle has been driven for a while just prior to fueling? Would weather conditions play a role (Florida vs Minnesota)?

My 300E always does that....and seems to have no issues running, so I'm not worried.

My 300E and e320 both whoosh when the gas cap is opened and always have. ithink its normal.