Three problems related to tank assembly have been reported for the 2006 Mercedes Benz E55. The most recently reported issues are listed below.
Just bought the car, and first time I filled the tank up (never topoff) started noticing a smell of gas, as the week went by smell increased. . . . . Followed forums suggestions and found a puddle of gas on top of the sending unit under the rear seat on the drivers side. Car is hard to drive due the smell, and I'm actually getting headaches from it. Own 4 mercedes including this, which is the latest model of all, and never had a safety issue that relates to gasoline on any of the others.
On 1/25/2012 I noticed a smell of gas upon refueling my vehicle. The dealer diagnosed the issue first as a defective fuel sender and after replacing the fuel sender as a defective gas tank. Essentially fuel was leaking from the gas tank under the back seat and pooling under the back seat. The smell of gasoline vapors was extremely strong and alarming. I replaced the fuel tank at my own cost.
Fuel tank leak.