OM612 Fuel Filter by-pass valve source of air leak

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helcam

New member
I know I'm late to the party, but........just some input for anyone who is frustrated with the air bubbles in the clear fuel line from the filter. My Sprinter is a 2003. Supposedly this fix is only for the 2002-2003 Sprinters. I must have re-primed my gas filter a dozen times trying different suggestions. Changed all the o-rings twice, changed to the Euro style filter with no water sensor or bleed screw, used better hose clamps.......still getting bubbles.
In one earlier post, I read someone mentioned the Fuel Return Valve on the top of the fuel filter. That is on the left side of the top of the filter, opposite the fuel supply line. Got one from Europarts San Diego. Part number 611 078 02 49 and cost $22.
THAT finally fixed the problem!!! Strange not many other people mentioned that so I didn't look there for a looooooong time. :bash:

Capture.JPG
 
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hkpierce

'02 140 Hi BlueBlk Pass
Re: Found a Fix to Fuel Filter leaks '02-03 T1N

helcam said:
I know I'm late to the party, but........just some input for anyone who is frustrated with the air bubbles in the clear fuel line from the filter. My Sprinter is a 2003. Supposedly this fix is only for the 2002-2003 Sprinters. I must have re-primed my gas filter a dozen times trying different suggestions. Changed all the o-rings twice, changed to the Euro style filter with no water sensor or bleed screw, used better hose clamps.......still getting bubbles.
In one earlier post, I read someone mentioned the Fuel Return Valve on the top of the fuel filter. That is on the left side of the top of the filter, opposite the fuel supply line. Got one from Europarts San Diego. Part number 611 078 02 49 and cost $22.
THAT finally fixed the problem!!! Strange not many other people mentioned that so I didn't look there for a looooooong time. :bash:
Click to expand...
I was testing mine with a MityVac. I found that the valve held vacuum from the filter side (the part that goes into the filter)

Bypassvalue pressureOK.jpg

But it would not hold vacuum in the by-pass direction. I could actually hear the leak - but I could not see it or find it. Trash.

Bypassvalue pressureNone.jpg
 
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bobatthebeach

New member
after replacing fuel filter twice,I got all o rings replaced and put good clamps on all hoses, I replaced fuel return part and then used pressure at the fuel cap to force air bubbles out. I now have clear fuel running through the new fuel line from filter to pump. this is at almost 200 K ,this is the 1st time ever I have not had air bubbles coming out of the filter, this by the way was the 8th filter change. Did not like changing it the 1st time or the last, but there it is. I also had a Hengst filter that put out an almost white foam , way different than the usual bubbles, maybe contaminate in the filter. Bobatthebeach
 
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hkpierce

'02 140 Hi BlueBlk Pass
I found this diagram that provides more information on the recirculating valve on top of the fuel filter. The valve circulates the fuel from the rail into the filter below 30 degrees C, and into the tank above 30 degrees C.

Screenshot 2023-04-19 075711.jpg
 
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