W211 Fuel tank leak
 

Hi there,

I seem to have some fuel leak on my tank. It's on the left side just in front of the left rear tire. It smells fuel. I took out the bottom cover and wheel well cover and saw there was a history of previous leaks as there was marks. I just filled up and noticed this. When I am on 1/2 tank I don't smell fuel. Only when new tank full.

I also opened the rear seat and took out the cover to the fuel pump and i saw a puddle of gas right on the rim of the fuel pump. I clean this with a rag and shook the car and drove it around but I could not get the leak to replicate.

Any suggestions where this leak might be coming from? I saw in one forum that there was exactly the same leak but unfortunately the guys contact details were no longer available.


If there are two of us, I'm pretty sure this is a defect in the W211 fuel tank.


Thanks!



Francis

It sounds like the seal(s) at the top of the sender is leaking. I'm guessing that someone tried to re-use them after replacing a fuel level sender/pump/filter? I've never seen one of these seals leak for no apparent reason, but I've seen a few leak when re-used.