Everytime I get my car filled up, and garage park it, I smell of gas
on 2007 Mercedes-Benz C280 4MATIC

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
I do not top it off, and over time the smell is stronger and lasts longer
(2) Answers
Check your fuel filler neck. It may have rusted and some fuel splashes through this small hole in the neck. Fumes from the tank will also escape through this gap..Do you have a check engine light on? Also check to make sure all hoses are attached and not cracked in this area.
Hey Buddy, I had that same issue for almost 6 months. Then my shop realized, it was the gasket underneath the back passenger seat on the right that needed to be replaced. I got that done & wow, no more smell :)