damnDSM

The w124 fuel gauge stopped working last week. My wife ran out of gas (twice) and then started complaining of a strong fuel odor. The odor was noticeable mostly in the trunk and cabin of the car. The carpet in the trunk was soaked, and there were puddles of petrol in the spare tire well, under the tank, and down in the little well on the drivers side/trunk.


I removed the gas tank today and i found that it has imploded, at least 1gal worth and formed a crack at the crease. It is only visible from the back side, between the rear seat and tank. I used some developer over the entire tank to expose any other cracks, but i did not find any, though I wouldn't be surprised if more formed over time from the indentation. I plan to dremel out the 1/4" crack, and tig weld it. Pictures tomorrow.


My questing is this.
Is this a common problem with running a 1995 E320 completely empty?

Or is the evap canister definitely a culprit?
How can i test this on the w124?
Where the hell is it?

ptoro01

Replacing it might be a better idea.

The charcoal canister is behind the front passenger wheel inside the fender.

neanderthal

Very rare.

The tanks location makes it very safe from impacts or hits.
This is the first i've heard of a tank just cracking. Doesn't mean it can't happen

HAL STEINER

do a search on HAL STEINER
the problem is the REGENERATION VALVE replace it on new installation $30.
if you have the tank out it will be on the bottom left side of tank hose runs forward to charcoal filter in front left wheel well
had this problem tank collapsed only indication that something was wrong was a vacuum on gas cap when I opened to put in gas

go buy a junk tank I paid 70 for a tank

pwogaman

I have an extra from my 1991 300E parts car. If you put your location in your signature and you're close by I will give it to you.

damnDSM

Is this the "Regeneration Valve"? (its a one-way check valve, that broke on removal.)




Note: this tank is thin, and welds like garbage. It seems to be galvanized, and I think its un-weldable, even with silicon-bronze filler.

pwogaman

Did you have something heavy in the trunk slam into the tank after a jolted stop? I have a hard time envisioning how else your damage could have occurred.

HAL STEINER

Yes that is the regeneration valve.
your tank did not collapse very much
when mine did this it would not take any more than 2.5 gal of gas.
it was visible when i removed the vanity panel in the trunk.
anyhow do not try to repair get a tank from junk yard
get a regeneration valve on ebay and a NEW gas cap.

been there done that

again for others out there when you hear a VACUUM when you remove your gas cap do not hesitate change the regeneration valve.

damnDSM

I have always heard a vacuum noise when opening the gas cap, especially when the tank is near empty. There is definitely an issue with too much vacuum. After installing a salvage yard tank, and mb tank vent valve, there is still an overwhelming amount of vacuum in the tank. So much that I heard the fuel tank flexing while driving. I immediately pulled over, and tried to remove the cap... Which was nearly impossible because of the vacuum. When I was finally able to remove the cap, I heard the tank make a "boing" noise as it sprung back to normal...

damnDSM

Can someone explain the exact evap line route? Or maybe post a diagram? I can't seem to find anything on here.

emendonca

I own a w124 300 1991 and I had almost the same problem. My tank did not crack but it shrunk 40%, from 75liters to 46 liters.
The charcoal canister was clogged