Here is a cool product for those of you running alternative fuel in your Mercedes Diesel. If you have been running biodiesel for any length of time or even WVO in your factory fuel tank you may have noticed that you gas cap seal is swelling up and looking kind of ugly. We recently found a source of gas cap seals that will help solve this problem. They are not made out of viton so I can not guarantee that they will last forever but they are made out of a synthetic material that certainly lasts a lot longer than rubber. We sell this seal in sets of three in case you have multiple cars (and yes they even work better on gas vehicles) and will have a spare when needed. They fit all Mercedes gas caps from the early 1960s up through 1995.