depressurizing the fuel system?

[MercDane]

Hi all,

I'm gonna be changing the fuel filter on my W203 220 CDI and was wondering if I need to depressurize the fuel systems/lines before undoing the clips to avoid getting sprayed.

Thanks a lot in advance.

Gabriel

p.s. I've also bought the fuel line seals (small green o-rings) that came in a pack of 8. I want of change as many as there are in the system. Are there not only six of them though (saw that in a diagram someone had posted)?

 

[BlackC55]

Only six seals.

No need to de-pressurise. Just fill the new filter to the brim with diesel.

 

[Danny DeVito]

And let it soak a few minutes then top up again

 

[MercDane]

Hi gents,

Thanks a lot. So no need to depressurize.

I'm still a little unclear about the fuel lines seals though. Proser once told me to chec kfor ait bubbles when starting the car from cold by having a look at the fuels lines from the filter to the pump and pump to the fuel rail. He said the seals/O-rings are on the end of the fuel lines. I see the line going from the pump to the rail has special clips, which I suppose the seals fit on the inside of -in some kind of groove maybe?

But my filter has two hoses on top of it with plain hose ends that are clamped onto the filter in- & outlets with ear/pinch clamps and no o-rings to be seen. Also on the diagram (I'm attaching it and it's actually from a 270 CDI) two of the six seals go on the filter, so I have at least two seals out of six I don't know where to fit. Any thoughts? Sorry if the question is trivial. I'm entirely new to Mercedes.

Thanks.

Gsbriel

 

[LastMinute]

I think you attached the wrong thing there.

A 2002 C220 CDI should (?) have an OM611 engine with fuel system looking like this, but your description of the fuel filter makes it sound more like the later OM646 engine, looking like this. In the latter case I don't think there are any O-rings to replace; everything is held together by jubilee clips. In the former case there are O-rings on the end-pieces of all the plastic pipes where they push into their fittings.

 

[MercDane]

Thanks a lot. There probably is no o-rings then. I have a problem with the engine starting and cutting out within 2 seconds on cold starts and I was told it might be the o-rings, so I thought I'd replace those before going to Mercdes for a pricy diagnosis. I guess there is no way around that now.

Cheers,
Gabriel

 

[surreychris]

Hi Guys
I'll be changing my O rings in the new year as i also have an airleak and trouble starting when cold. I may as well change the fuel filter at the same time.

I was worried about having to bleed the air out of the fuel system once it had been opened up.

How do i bleed all the air out once i have done this so that the car will start?

Thanks

Chris

 

[Danny DeVito]

Self bleeding i believe, just see above with the filter

 

[Lord-WYBMAnE220]

It's a little self-bleeder, me old mucker - indeed, you shouldn't even need to fill the empty filter.
When it's all reassembled, just leave the ignition on until you hear the pump stop whining and start her up.
Job done (unless it's very different from my W211 ... which now I've posted this, it probably will be).

 

[Lord-WYBMAnE220]

Self bleeding i believe, just see above with the filter

Hey ... shouldn't your name be Vanny DeVito ?

 

[grumpyoldgit]

It's a little self-bleeder, me old mucker - indeed, you shouldn't even need to fill the empty filter.
When it's all reassembled, just leave the ignition on until you hear the pump stop whining and start her up.
Job done (unless it's very different from my W211 ... which now I've posted this, it probably will be).

Think he's probably sorted it by now mate. 3 year old thread

 

[Lord-WYBMAnE220]

Think he's probably sorted it by now mate. 3 year old thread

Holy threadromancy!