E 290TD air in fuel line
05-22-2011, 06:07 PM
#1
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W210 E290 Turbodiesel
E 290TD air in fuel line
Since I bought this car (E290TD sedan 97`) 2 years ago I have a problem with air in fuel line.
So first of all, when engine is running and I`m throttling it up I only see air bubbles in one line number 188 (from fuel filter to fuel pump) from diagram below.
I marked the fuel flow direction with green arrows, and air in fuel line with red dots.
I changed both plastic fuel lines (numbers 167, 188), diesel fuel filter with o-ring (number 62, o-ring number 68) everything new bought in MB Service.
After I changed those parts I don`t see any difference.
I don`t know how air is getting into fuel line number 188 because I don`t see any air in line 167 (from fuel thermostat to fuel filter). It looks like the air is getting in somewhere near diesel fuel filter (but the filter is new original MB part with new o-ring 68 on banjo bolt) by the way there is an error on diagram because there is no place for second o-ring (number 65) on this banjo bolt, picture below.
Does anyone have an idea what to do to keep air out of the fuel line?
So first of all, when engine is running and I`m throttling it up I only see air bubbles in one line number 188 (from fuel filter to fuel pump) from diagram below.
I marked the fuel flow direction with green arrows, and air in fuel line with red dots.
I changed both plastic fuel lines (numbers 167, 188), diesel fuel filter with o-ring (number 62, o-ring number 68) everything new bought in MB Service.
After I changed those parts I don`t see any difference.
I don`t know how air is getting into fuel line number 188 because I don`t see any air in line 167 (from fuel thermostat to fuel filter). It looks like the air is getting in somewhere near diesel fuel filter (but the filter is new original MB part with new o-ring 68 on banjo bolt) by the way there is an error on diagram because there is no place for second o-ring (number 65) on this banjo bolt, picture below.
Does anyone have an idea what to do to keep air out of the fuel line?
05-23-2011, 10:21 AM
#2
I'm assuming your fuel filter is probably the same set up as mine. Given that, you are probably incorrect about the number 65 o-ring not needing to be there. I believe there is a rubber o-ring that goes between the fuel filter and where it mates with the filter mount. You have to be very careful when installing the filter to not tighten too much or damage that o-ring.
You could also be getting air from the SOV. The Shut Off Valve can start to leak in air. It really causes big problems once it goes completely.
Are you finding any fuel under the car after operating it or letting it sit?
You could also be getting air from the SOV. The Shut Off Valve can start to leak in air. It really causes big problems once it goes completely.
Are you finding any fuel under the car after operating it or letting it sit?
05-23-2011, 07:07 PM
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W210 E290 Turbodiesel
I'm assuming your fuel filter is probably the same set up as mine. Given that, you are probably incorrect about the number 65 o-ring not needing to be there. I believe there is a rubber o-ring that goes between the fuel filter and where it mates with the filter mount. You have to be very careful when installing the filter to not tighten too much or damage that o-ring.
But I still don`t see why there should be o-ring in the centre of filter because as you can see on picture below there is a rubber ring in the middle of the filter already installed.
Bubbles of air are going from fuel filter to pump via fuel line number 188 (red dots) and shout off valve is installed in the pump so I guess it is not SOV fault and something is wrong with filter mount or banjo bolt or damn o-ring / o-rings on banjo bolt number 80.
05-24-2011, 11:05 AM
#4
Ok, so how should I install o-ring number 65, something like this?
Yes. Install the o-ring just like that. That is how it's installed on mine.
But I still don`t see why there should be o-ring in the centre of filter because as you can see on picture below there is a rubber ring in the middle of the filter already installed.
I thought you may have removed the rubber ring in the middle of the filter which you have pictured. No need for anything additional there. Keep everything as is.
I don`t see any sign of diesel fuel under the pump or engine.
Bubbles of air are going from fuel filter to pump via fuel line number 188 (red dots) and shout off valve is installed in the pump so I guess it is not SOV fault and something is wrong with filter mount or banjo bolt or damn o-ring / o-rings on banjo bolt number 80.
Yes. Install the o-ring just like that. That is how it's installed on mine.But I still don`t see why there should be o-ring in the centre of filter because as you can see on picture below there is a rubber ring in the middle of the filter already installed.
I thought you may have removed the rubber ring in the middle of the filter which you have pictured. No need for anything additional there. Keep everything as is.
I don`t see any sign of diesel fuel under the pump or engine.
Bubbles of air are going from fuel filter to pump via fuel line number 188 (red dots) and shout off valve is installed in the pump so I guess it is not SOV fault and something is wrong with filter mount or banjo bolt or damn o-ring / o-rings on banjo bolt number 80.
05-24-2011, 02:52 PM
#5
