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Had a recent issue with the E350 that surprised me, so I wanted to share. Obviously the issues related to fuel leaks on w211's are well known and documented, but I just went through a similar issue on my w212. Heavy fuel smell outside the car, especially after fill up. Brought it to my indie and sure enough the sending unit/pump assembly in the top of the tank had cracked and fuel was pooling. Hadn't really seen/read anything about this type of issue on the newer models.
Pretty disappointing, as you would think MB would have made it a priority to not repeat the same issue as past models. On top of that, I am literally 6 weeks and 500 miles outside of factory warranty...
Had a recent issue with the E350 that surprised me, so I wanted to share. Obviously the issues related to fuel leaks on w211's are well known and documented, but I just went through a similar issue on my w212. Heavy fuel smell outside the car, especially after fill up. Brought it to my indie and sure enough the sending unit/pump assembly in the top of the tank had cracked and fuel was pooling. Hadn't really seen/read anything about this type of issue on the newer models.
Pretty disappointing, as you would think MB would have made it a priority to not repeat the same issue as past models. On top of that, I am literally 6 weeks and 500 miles outside of factory warranty...
I would immediately pick up the phone and call MBUSA and ask for a goodwill repair. You might also want to report your problem to NHTSA at safercar.gov
@ CEB - think MBUSA would still consider doing something even if i've already paid to have the issue resolved on my own by my indie? guess it doesn't hurt to try eh...
@ CEB - think MBUSA would still consider doing something even if i've already paid to have the issue resolved on my own by my indie? guess it doesn't hurt to try eh...
I would certainly try. Being so close to warranty should be something they'd want to fix - especially since it is a safety issue.
However, the fact that it was corrected by an indie might complicate matters but what does asking cost? Often they'll split costs too.
Call your indie ASAP and see if they still have the old part. The manufacturer may want it if it is still available.
As an aside and not to make you feel bad - but as advice to others - the MB dealer might have actually done the repair gratis had you taken it there. Most would call MB without you asking and try to work a deal.
In hindsight I definitely should have, but my line of thinking was well it's out of warranty, I'm SOL better take it to my guy....
I called MBUSA, lady said it may be an issue since I already took it and had it fixed on my own, but she's going to try and get someone to resolve this. One good thing is that my indie got the parts from the dealer, so even if my angle with MB is to just reimburse me for the parts, that would make me feel a whole lot better.
In hindsight I definitely should have, but my line of thinking was well it's out of warranty, I'm SOL better take it to my guy....
I called MBUSA, lady said it may be an issue since I already took it and had it fixed on my own, but she's going to try and get someone to resolve this. One good thing is that my indie got the parts from the dealer, so even if my angle with MB is to just reimburse me for the parts, that would make me feel a whole lot better.
Isn't it funny how hindsight is always 20/20?
Follow Konigstiger's advice (whatever it is) - he always has good advice.
For what it's worth, my 211 started leaking fuel also, and the car probably had 85K miles on it at the time. Took it to a local MB dealer and while talking to the SA about it the SM happened to walk by and over heard part of the conversation. He interjected and said, basically, "say no more, Sir, we will replace the entire fuel system at zero cost to you".
Hi Folks,
My 2012 E350 (W212) has a fuel leak at the point where the fuel line connects with the top of the unit/pump assembly at the top of the tank, underneath the driver side rear seat.
I started to take it all apart but was unable to figure out how to disconnect the fuel line from the white plastic pump unit.
See attached photo.
Questions:
how do you disconnect the fuel line from the white plastic unit cover?
How difficult is it to replace the fuel line/connector?
That blue fuel hose BLACK connector is a PUSH-TO-RELEASE type at the base to release, kind hidden from view.
So ur o-ring is probably leaky.
There is 5 BAR of pressure in that blue fuel hose, becareful. See the link and study it well. Ask more when you need it yah.
Battery disconnect is best-safest and a MUST to prevent fuel pump priming itself.
Had a recent issue with the E350 that surprised me, so I wanted to share. Obviously the issues related to fuel leaks on w211's are well known and documented, but I just went through a similar issue on my w212. Heavy fuel smell outside the car, especially after fill up. Brought it to my indie and sure enough the sending unit/pump assembly in the top of the tank had cracked and fuel was pooling. Hadn't really seen/read anything about this type of issue on the newer models.
Pretty disappointing, as you would think MB would have made it a priority to not repeat the same issue as past models. On top of that, I am literally 6 weeks and 500 miles outside of factory warranty...
I had the same issue. My fuel filter assembly had a crack and was leaking fuel inside the cabin. Found this video on You Tube. I followed the instructions. Now it is fixed, no more fuel smell after I fill up
I am a bit confused in researching this issue. I have the same fuel leak smell. All the videos I have see all correspond to replacing the JUST the plastic cover on the passenger side and the filter unit on the drivers side and seals if needed and leaking. I called the dealership to get an idea of what they would say and they quoted me $2100 to repair both sides. I could not get more definitive answer as to whether they are replacing the filter and pump too which I assume is built into the cost. But why replace the filter and pump, if not needed and it is just the cover that is leaking on the passenger side. I did not know to ask this as I had not done the additional research yet. I know if the passenger side cover is leaking that is necessary but the pump may not be, correct. Unless the dealer is just trying to cover themselves and make money. Thanks for the help.
Last edited by MPTrader; May 13, 2025 at 05:49 PM.
The fuel leak smell if is inside the car, meaning from these two units :
The leaky points are not only the white if filter and blue if pump plastic body/cover of fuel pump or fuel filter, cracking, it could also be the big orange o-ring underneath it failing.
It can also be the o-ring of the blue plastic hose of filter output.
PUMP
.
See the big orange o-ring.
FILTER. Also uses the same big orange o-ring.
Thus 2 old o-rings in my hand. I use new o-rings. A MUST DO.
This is the output hose of filter to engine, it has o-ring. U can't buy this o-ring, you must buy 1 set blue hose.
To replace this blue hose most likely your fuel tank must come down. I tried replacing this blue hose and failed, because I do not want to drop my fuel tank.
Maybe drop of 2-3 inches is enough, no need to drop 100% to the floor. Me worried the main fuel filler hose neck will break, also plastic. when I lower fuel tank even only by 2-3 inches.
Good luck finding the leak..........
Last edited by S-Prihadi; May 14, 2025 at 05:46 AM.
These region if leaking may also contribute to fuel smell inside the car .
US cars I think have sensors able to detect loss of sealing of fuel tank vapor. Fuel EVAP problem u guys call it.
My car does not have such sensor.
1 is vent pipe, plastic, 2 is main fuel filler plastic pipe
@S-Prihadi thanks for the detailed information. I do see the blue hose. To confirm that originates on the filter side? Where does the the other end terminate? Also when you mention the fuel filler hose neck will break are you referring to the male portion of the filter the 90 degree fuel line connects to. Hopefully the good thing is that there is no perceived smell inside the car and the smell outside in the garage stopped after driving 60 miles. So it appears to occur when the tank is filled up. Thanks again.
Last edited by MPTrader; May 14, 2025 at 11:29 AM.
@S-Prihadi thanks for the detailed information. I do see the blue hose. To confirm that originates on the filter side? Where does the the other end terminate? Also when you mention the fuel filler hose neck will break are you referring to the male portion of the filter the 90 degree fuel line connects to. Thanks again.
Item no 10 is the blue plastic fuel hose. The one at engine bay item 50 is rubber with braided steel jacket, I have renewed already.
.
FUEL FILLER HOSE.- Big fat plastic
It is all moulded as 1 piece fuel tank you see, thus unlike rubber hose where we have room to flex it.
There are a few types of w212 fuel tank, but this is what I believe ALMOST similar to mine: https://www.ebay.com/itm/135011603595
This one seems to be steel pipe version at tank fill. Mine 100% plastic.
@S-Prihadi Wow, that definitely looks painful. It seems like splicing the fuel line with a new connector would be a better alternative as long as it could be done without leaking. I do think my model is a bit different from some of the video I have seen - at least as far as the filter and pump are concerned and the pump cover which I have been told is a likely culprit. Will have to check it out when I get a chance asap. Thanks
@S-Prihadi Wow, that definitely looks painful. It seems like splicing the fuel line with a new connector would be a better alternative as long as it could be done without leaking. I do think my model is a bit different from some of the video I have seen - at least as far as the filter and pump are concerned and the pump cover which I have been told is a likely culprit. Will have to check it out when I get a chance asap. Thanks
Too risky, I will drop my subframe this year or next year anyway to replace all its bushings and the DIFF ones too. so I will replace that blue fuel plastoic hose.
Funny enough is that this plastic fuel hose is also found on the W204 C200 of 2010 ( my friend's, so now 14th year ) and it is due to cooler operation temperature is still ok and the one on the engine side,
rubber hose version started cracking ( no leak yet ).
The fuel leak smell if is inside the car, meaning from these two units :
The leaky points are not only the white if filter and blue if pump plastic body/cover of fuel pump or fuel filter, cracking, it could also be the big orange o-ring underneath it failing.
It can also be the o-ring of the blue plastic hose of filter output.
PUMP
.
See the big orange o-ring.
FILTER. Also uses the same big orange o-ring.
Thus 2 old o-rings in my hand. I use new o-rings. A MUST DO.
This is the output hose of filter to engine, it has o-ring. U can't buy this o-ring, you must buy 1 set blue hose.
To replace this blue hose most likely your fuel tank must come down. I tried replacing this blue hose and failed, because I do not want to drop my fuel tank.
Maybe drop of 2-3 inches is enough, no need to drop 100% to the floor. Me worried the main fuel filler hose neck will break, also plastic. when I lower fuel tank even only by 2-3 inches.
Good luck finding the leak..........
for the small oring in the blue hose….can it be replaced similar to an oring in an abc hose connection? It looks accessible. It can be a bit of a pain but with a little pick and a replacement fuel tolerant oring it should not be too difficult.
for the small oring in the blue hose….can it be replaced similar to an oring in an abc hose connection? It looks accessible. It can be a bit of a pain but with a little pick and a replacement fuel tolerant oring it should not be too difficult.
Yes, it is possible but the o-ring has to be accurately the same and fuel resistant and up to 7 BAR ( 102 psi ) ready.
If that o-ring failed, I think sooner or later the blue plastic hose and the black plastic clip body will go too.
Afterall it is plastic.
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when I lower fuel tank even only by 2-3 inches.
