[Master Captain]

Hi All,

I have had a sporadic smell of fuel in the cabin for over a year now... I have read the posts by others and some of my experience has been the same - usually happens on days when temps are between 40-55 degrees F, sometimes it can be smelled prior to starting the engine, and it may last several minutes to over half an hour.

The other day I tracked down the origin of the smell, prior to starting the car. I've attached photos.

The hose is attached at the underside of the round unit in the photo - the white arrow is pointing to the hose that has the fuel on it.

The other photo is a close-up of where the hose attaches to the 'round unit'. The wet fuel can be seen on the hose and clamp.

Either the hose is leaking, the clamp holding the hose is not secure, or the part to which the hose is attached is either leaking or the barb to which the hose is clamped has cracked. The leak is small (at the moment) and only seems to be wetting the hose, and not dripping. But a fuel leak can't be good under any circumstance...

Before I remove the hose to see if the clamp, hose, barb, or the unit are the problem, can someone tell me what the part/unit is called?? I've searched MB part sites using several variations of the numbers shown on the unit (the round part) and can't find anything that is fuel system related... very strange.

Thank you!
Peter

 

[Geo K]

May be related to your issue > In your research, please include Fuel rail leak CLA250

 

[Geo K]

Also, I recall starting a thread on this subject on 12/20/21 "NHTS Recall 21V961"

 

[Master Captain]

First - apologies for misspelling 'Located' in my headline...

Geo K - Thank you for your 2 replies. Appreciated!
However, my car did not fall under that recall, and as the fuel leak is isolated to the one spot shown in the photos, I do not believe it to be the fuel rail (though I may be wrong).

I am trying to determine what the round part to which the hose is attached is called. When I enter any combinations of the visible part # into a MB parts site, it comes back with no image and "Soundproofing" as the part... very confusing.

I have looked for an engine and fuel system schematic but this part doesn't show...

Thanks,
Peter

 

[Geo K]

Peter > If no Member responds, phone or show photo to your MB Parts Dept. and get a price quote??

 

[Kishow]

I had a warranty repair a while ago with the same problem. I didn't check it with my own eyes, but I heard that there was a leak in the low pressure line of the fuel pump. We'll let you know when we find the receipt and confirm the correct name or part number. I don't know where they are now.

 

[pa4ul]

that is the high pressure fuel pump under that cover.

 

[jmc]

if someone mucked with that joint
they may have contaminated the hose / barb connection area
quick fix would be to cut back join new hose section with coupler clean barb and reinstall with new clamp

 

[Master Captain]

that is the high pressure fuel pump under that cover.

ahhh... thank you for confirming!

 

[Master Captain]

if someone mucked with that joint
they may have contaminated the hose / barb connection area
quick fix would be to cut back join new hose section with coupler clean barb and reinstall with new clamp

Thank you JMC! I found a description of the identical problem some people were having with the C300... someone who sounded very knowledgeable (i.e. a mechanic) said that replacing the clamp corrected the problem. Several others followed his advice and did the same and resolved their issue.
The car has only been serviced by me the last few years and I haven't touched that hose, to my knowledge, though it is close enough to the air filter that I may have inadvertently bumped it when changing the filter. Or maybe the clamp has just lost it's tension a bit after 8 years...
Hopefully there is enough extra length to the hose so I can trim an inch off and still reach the barb.

Will post after I get to fixing this in the next few weeks.

Peter

 

[jmc]

be careful
static reach may seem fine
but the motor torques during drives and could yank on the fuel line

 

[ClaNorway]

Same issue with my Cla 180 some time ago, smell of fuel in the cabin. The hose to the high pressure pump was dripping a little fuel just like yours. The hose had a little crack from inside the hose. So the solution change the hose and the two clamps.

 

[jmc]

nice to see some regular clamps doing the job just fine 🙂

 

[Master Captain]

Same issue with my Cla 180 some time ago, smell of fuel in the cabin. The hose to the high pressure pump was dripping a little fuel just like yours. The hose had a little crack from inside the hose. So the solution change the hose and the two clamps.

Thank you CLANorway! I need to get the fuel line part number and will then order that and the 2 clamps. The MB OEM clamps aren't expensive (only $2.50US here). Hopefully this will correct the issue.
and apologies for the delay in responding... I got married last week so I've been a a little preoccupied!
Peter

 

[ClaNorway]

Thank you CLANorway! I need to get the fuel line part number and will then order that and the 2 clamps. The MB OEM clamps aren't expensive (only $2.50US here). Hopefully this will correct the issue.
and apologies for the delay in responding... I got married last week so I've been a a little preoccupied!
Peter

Congrats! No problem glad too help! The part number is on the hose in one of the pictures, and i replaced the oem clamps as they are a pain too install (replacement in picture below).

 

[ClaNorway]

The clamps i used.

 

[Master Captain]

Congrats! No problem glad too help! The part number is on the hose in one of the pictures, and i replaced the oem clamps as they are a pain too install (replacement in picture below).

Thank you!
I saw the numbers on the hose but wasn't sure which is the actual part number... I'm guessing the 24647... number, will start with that one and then try others if no result. Hopefully the length is the same for the 250 as the 180.
and thank you for the heads up on the clamps.

 

[ClaNorway]

Yes that's the part number. Looks the same from the photos i have seen, but the dealer will definitely know if its correct. Good luck.