S-Prihadi

Gents,

I got to cut another fuel filter. Also VDO like my E400, but this one from W204. 100% the same design.
My E400 fuel filter autopsy is here ............ https://mbworld.org/forums/e-class-w...er-change.html


The duty of this fuel filter : This is a GDI engine




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The autopsy.



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Draining fuel from CLEAN SIDE.... Same case as my E400 which was 8 years old but 36,000KM only.
The freaking sealing design between clean and dirty side is so bad, dirty fuel can bypass paper filter element !!!!!






The fuel in the tank at time of fuel filter replacement. Left red fuel in the bottle is the fuel in use, Pertamina Pertamax Turbo 98.





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At this rate the stupid seal is allowing some dirty fuel to jump to clean side without going thru the paper filter element, I won't be surprised some GDI engines with such filter design,
will have its High Pressure fuel pump life no longer than 1.5 times the fuel filter life ...... for those pushing past 15,000 liters or 3,900 ish gallons burn between filter change.
I am setting for 25,000 KM or 15,500 miles for my E400 2nd time fuel filter replacement or 5-6 years, whichever comes first. Perhaps year 2028.


I am amazed at anyone in US having to replace fuel pump ahead of fuel filter of his/her W212 ( not modified, standard GDI engine ).
I can safely say that it is from dirty fuel filter and pump got over worked and die young.
The pressure sensor which N118 fuel computer is reading is at the OUTPUT or CLEAN side of the fuel filter housing.
So , N118 does not know a dirty fuel filter, it simply try to achieve the 5 to 6.5 BAR* approx pressure it is designed to ( *GDI engine ) at filter CLEAN side .
So, if fuel filter is dirty... the fuel pump suffers high head/pressure, while N118 does not know that fuel pump has to deal with that high GROSS pressure, because it is at the fuel filter DIRTY side,
where there is no pressure sensor


Why why MB ? Why such poor design of the sealing ???
Why not use a good o-ring instead as sealing device and NOT use the brown plastic top hat and bottom hat of the filter element .



END OF REPORT & RANT
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CaliBenzDriver

Very interesting filter review. Now we have an additional reason why injectors get stuck by tiny debris.

You show us the chocolate colored dirty side... should we clean up the gas tank itself?

Remember your calculation for dew point to build up condensation in partially filled tank.

This fuel system is return-less meaning fuel content does not get heated by traveling back and forth to engine.

Only the 3-phases LPFP is cooled by our gasoline+ condensate.

JettaRed

iTrader: (1)

I wish the damned filter was external so you don't have to disassemble the car (I know, @S-Prihadi , that would take all the fun out of it) or drain the fuel tank.

By the way, where do you measure the fuel filter usage?

S-Prihadi

I always fill fuel to maximum full and zero the odometer and note down total mileage by the next fuel fill to maximum.
There I get my true average mileage for daily city driving. So I can use that for total fuel burn estimate over the life of the engine.
Better than looking at the car fuel economy mileage information on the middle display
It will be better fuel economy if I do long distance run out of town, but I rarely run out of town.
Overall I probably calculated 10% too much, but its ok to err on the side of caution.

Quint22

I input all my fill ups to fuelly. Works pretty good to keep track of everything and I can see my mileage and history. Not looking forward to doing this on my e250. Really wish there was a setup like the cummins with both filters external however I understand not alot of room. One of these days maybe Ill figure something out. Pretty sure back by rear diff there is room for a filter, just gotta figure everything out.

S-Prihadi

On yachts, our primary fuel filter ( Racor FG1000 ) is not on the engine and secondary fuel filter spin-on by engine builder in on engine ....but both at SUCTION side of low pressurefuel delivery pump,
never at positive pressure side like W212. So even though Racor filter uses same concept where top hat and bottom hat which is also plastic and a seal, it does not get stressed to 6.5 BAR positive pressure

I was also thinking at some point on how to add on extra in-line low pressure drop fuel filter after the in-tank fuel filter, but it has to be less than 3 PSI pressure drop, or else my HighPress fuel pump
will not be happy.

For diesel engine, some of my friend on their Toyota-s 4WD, add small Racor spin-on fuel filter as added protection.
When I once had a Toyota mini-bus shaped car RWD, and is a diesel, 1st gen common rail unit, I replaced the fuel filter at every oil change or 5,000KM.
It is so cheap at US$7.00 only ha ha ha.... and at engine bay, so very easy to replace. I respect common rail level of fuel cleanliness, maximum is 2 micron size allowed if we want it super clean.

JettaRed

iTrader: (1)

The R230 has an in-line external filter. A bit of a pain to get to, but still much easier than disassembling the rear of the car to do the R231. Of course, the change interval for the external filter is 60k miles or 4 years, but I could live with that.

S-Prihadi

Aha, 4 ports..... It must be the fuel system is return to tank type...yes ?
W212 is returnless.

JettaRed

iTrader: (1)

Correct. Non-DI engine.

S-Prihadi

I did not spot any visible significant dirt in the tank, but I also did not shine my torch much into it.
I respect gasoline a great deal ... aka I fear them. When a lot of void airspace in a fuel tank like W212 and little fuel, I am scared of the Lower Explosive Limit being easier to achieve
It would be great if one has an air operated/powered fuel suction pump ( much safer ) to suck the gasoline out and give the tank internal a good wipe.

Condensation I am not too worried, it wont be much now that the tanks are not free air ventilated like say a boat fuel tank.
Our W212 with the fuel EVAP thingy is like a limiting device.