Costco fill ups are 4 miles from my garage. With that full of a tank you can smell it walking around the car. Half a gallon less and you smell nothing. No leak. I checked the gas cap, seems to seal fine. It's definitely coming from the back though. No smell under the hood at all. What do you think it is?

 

When the pump shuts off do you stop? Or do you add more until it’s full?

 

Good ideas, but i pullout right when it clicks. I'm wondering if there is a seal or some access into the tank at the top..

 

Something is broken to allow fumes out. I have no experience with that

 

I knew I wasn't dreaming - I found the similar thread in here ... be sure to read thru from #1 on ... #3 has the possible issue and solution:

https://mbworld.org/forums/glk-class...ling-tank.html

 

It can be the seal that the pump has under your back seat. You might want to pull your back seat out and check the pumps to see if they are leaking!!

 

If it’s cracked seal it, I’m sure it’s plastic , research what will adhere. I’m sure there are a lot of YouTube videos on this .if using a silicone check expiration date , most any product , silicone for sure goes bad fast.

 

Sort of off topic, but we had the same problem with a Jeep but it was made after Daimler sold off Chrysler. First just a vapor smell when filled, later it would actually drip on the floor under the tank.

It would surprise me if that plastic material wasn't hard to get sealers and such to stick to.

 

Back seat cushion and the two black covers need to be removed to have access to the fuel pump and the fuel suction unit.

Gasoline puddle. No smell inside the car.


Fuel pump and suction pump, both need to be removed.

Plastic epoxy did not fix the leak. There were tiny cracks around tube where the fuel line connects.

The new Fuel Suction Pump Assembly from FCP Euro

The tool I purchased at Amazon. You need a long breaker bar or long ratchet.

New unit in place.

This is what my wife’s 2013 GLK caused the fuel smell. It might help you troubleshoot yours. There’s a YouTube channel of a gentleman who shows more in detail the procedure of replacing the unit.
Senior Leigh. https://youtu.be/I-6rRazzeUY?si=XIpRE8VZUU-1oZ9u

I hope this helps you find your source of fuel smell.

 

Very common problem in aging W211 models.

 

So, @GLKwanter ... anything to report back with the gas smell ? Would be good to know.

 

If the smell is not inside the car, but rather outside the car at the rear as indicated in the OP, check for failed purge system. Focus on the canister, typically located inside the rear quarter panel near the filler neck. Remove the wheel arch liner nearest the filler neck to inspect.

 

I guess I'll be pulling the rear seat and those covers to inspect what's going on, and only filling a half tank till then.
I freaking love this ride..

 

I don't even feel like taking a car seat out to look under the seat, that sounds like even more work lol.. oh where could it be..

 

Found mine on zon for $46.. what could go wrong.. lol

 

Pulling up the seat is not a big deal. I watched Senior Leigh's video a few times and it looks straightforward. Simply do the job step by step.

Same with the carbon canister, if you go down that diagnostic path. Videos on yt are available for this and it looks straightforward. Wheel off, wheel arch liner partly off, then you can see the canister.

 

Smell and crack on passenger side, same place as everyone else. Driver side no smell no crack, seems moistish though.. probably need everything lol

 

Seems like you found it. Now for the next steps...

 

Wouldn't be a bad idea to pack a fire extinguisher until you get it resolved.

 

Would be a good idea to always pack a fire extinguisher in every vehicle you own - and not a tiny or small one.

 

There are sealants that should hold up for awhile , one is by Permatex

 

$63 for the elcheapo fix from amazon (A2044700494 & 2114710179)
$63 for 3/4 of a tank of 91 octane at Costco
Garage not smelling like gasoline, priceless
She's perfect again!

 

@GLKwanter ... glad to read it was a fairly simple and inexpensive fix.

And also thanks for sharing the info and the results!!

 

Did you ever address anything on the left side cover? I've been looking for a part number for that one, which looks pretty much identical to the right side (passenger) cover, but with a plug for the fuel pressure sensor (I believe) sticking through the center "tube" (blank on the right side cover). I've seen lots of parts breakouts that funnel me to parts that look nothing like the cover on my 2012 RWD "project car". I might have to resort to removing the cover and just slathering the suspect portion with epoxy (both sides).

 

Here's the part diagram from MB.


The right side cap (the one I replaced in my video) is part #135 above. Thing is, the left side cap looks identical to the right one, other than the plug (fuel pressure sensor?) coming through the center where the right side has a blank "tube" with nothing in it. The part #100 in the diagram is a fuel level sender that looks nothing like my cars. Here's a (kind of blurry - sorry) shot from my video showing the left side cover...


This is just getting curiouser and curiouser...