I have a unique problem with my W124 E 220, Fuel Tanks gets full exactly with 3/4 of its fuel capacity. Fuel gauge shows 3/4 full, but tank can't take anymore gas.

This started after leaving at local MB dealer to fix idle surge, looks like someone held air into the pipe running form charcoal filter as purge valve was full of charcoal bead's when I checked this weekend.

I just want to have some idea before leaving it back at the dealer...

Thank you

You have made a good observation....damaged charcoal cannister is most likely the problem.

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MERCEDES Benz Master Guild Technician (6 TIMES)
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44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

On my 300SD I have been told that beneath the first aid kit is the fuel (send?) unit that can be removed with a 22mm socket and cleaned. Appearantly this often fixes the problem. Mine is empty when their appears to be 1/8 left.

In my case sender is fine and gauge reports correct fuel level, but tank gets full with 3/4 of its capacity, i.e my tank capacity is 70 Ltrs but I can only fill 52.5 Ltrs before it spills out.

You just contradicted yourself. Does it read full or 3/4.
If it is reading full and not getting more fuel in. I have seen when the charcoal canister fails that the tank collapses.
If it is reading 3/4 when the tank is full then the sender is at fault.

Fuel gauge reads 3/4 when tank can't take anymore fuel. Tank capacity which was 70 Lts now can accumulate only 52.5 Ltrs before it spills out.

If I happen to replace charcoal canister is there anything else I should take care while doing this job (like replacing other maintenance parts related to fuel tank) ?

Thanks

On that car there isn't other parts except a check valve.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Any chance that someone drove over something and dented the lower part of the fuel tank? A dent would cause the fuel tank to hold less fuel.

A visual check will do

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Fuel tank denting can be ruled out since it is behind the rear seat and above rear axle? will check it anyway.