Nessie

Can someone confirm if the fuel tank has an additional built in pump that cannot be replaced if faulty. I have been advised my only option is to buy a new fuel tank. I have replaced the external fitting pump but it didn't fix the noise problem. HELP!!

Chode McBlob

As far as I know, most countries won't even have the external filter assembly (for petrol models) - I believe it is only fitted as an option for lower fuel grade countries.

The filter-pump block inside the fuel tank is replaceable (155k miles or 15 years, according to the MB schedule for my car), whether it is more economical to replace the entire tank is a different matter, but I suspect a brand new one is rather costly.

Notes on retrofitting additional filter (which is what you have already replaced, right?):






Replacement of the main filter/pump in the fuel tank:



I was actually thinking of adding that external filter to my car, as a precautionary measure - too many stories about poor maintenance of fuel tanks at forecourts, here in the UK ...

PS The red codes in above are the document numbers (Mercedes WIS) - let me know if you need any of these to help your mechanic do the job.

Nessie

Thankyou most helpful information I have received. My dealer insists, backed up by written reply from MB, that a new tank is required. Cost $A1900. Free installation.

Chode McBlob

Most puzzling ...

Can you refer your dealer (and MB) directly to these documents from the Mercedes WIS:

AP47.20-P-0780AK
AP47.20-P-7000AK

What is your engine code?
Maybe these are not relevant to your car?
It's certainly applicable to mine - 266.960 (2035cc petrol)

Nessie

Sure is confusing. Mine is a A170 (1700cc's) Classic, W169 series. 1st build 2005. Engine No 266940300 etc
I have replaced the pump and filter as shown. MB advise there is what they refer too is a Jet suction pump housed within the tank that cannot be replaced. The wining noise is definitely coming from the tank and not the pump/filter that I replaced. Hope that this is helpful for you. Regards

Chode McBlob

Ah, maybe it's a different pump then?

I have a very limited knowledge of mechanical stuff

Just to clarify - the fuel filter/pump you've replaced - is it the outside one, like here:




or, the one inside the fuel tank, like this:




If it's the latter, then that's it: that's your main fuel filter/pump.

Nessie

Its the latter, the one inside the tank. Thanks.

Chode McBlob

Ah, okay - now it makes sense.

I first thought you had, and replaced, the outside filter, but once you've mentioned the cost, it was strange that, an Australian car would be fitted with a "lower grade fuel" additional filter ...

In that case, I'm afraid you have to go with what your dealer said - I didn't even know there was another pump in the tank, something to keep in mind for the future ...

Russell Ormerod

Jet suction pump has no moving parts and cannot wear out or fail!
It's simply a syphon pipe.