Terry is correct, it is not the fittings but the o-rings which seal them on the ends...if they leak you can replace only the o-rings to improve the seal. If you are not using the stock MB o-rings you might want to double check the sizes though to make sure you have the right ones on them, there are a couple of different sized rings on those fittings.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

That line should have the 2.5 x 8mm o-ring. I doubt you could get one of the larger 2.5 x 10mm o-rings to go in the hole.

I'd stick it in again and make certain you hear two clicks as it seats and if that doesnt work try a little silicone grease on the o-ring.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

When I initially put them in with the new o-rings they were very tight to get in. I think while I was working with the plastic tabs I probably cracked and just made them to pliable or something. Point is when I first inserted them it was nice and tight, now loose. I'm going to purchase these 2 lines and already ordered some more of the Viton o-rings as I only have 2 left.... Can I order these from FastLane and recieve them soon?

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#dieselFLEET
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'97 E300
'99 E300

And you don't even smoke weed - wtf rookie? LOL

I can tell you that a bubble in the line is not 'normal' despite what someone has posted..however, as someone else posted, there may be some residual air in the system after all this work you've done that will go away after a good drive. If not, possibly your connections aren't tight like you suggest.

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2004 Ram 2500 Cummins HO
2000 Jetta TDI
1999 E300 (sold)

The line being discussed is the fuel line form the fuel pre-heater/thermostat leading to the pre-filter. It is perfectly normal and occurs on ALL 606.xxx's. It drains back at shut down due to vacuum present in the tank which pulls the fuel down the feed line toward the tank as soon as the S/O valve closes. My personal feeling is that line contains vacuum rather than air which is why that "bubble" does not create a hard start condition.

From personal experience I can attest that a bubble that large in any OTHER fuel line is nightmarish to get out.

If you still had yours you would be able to see that.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

YEAH...AND we'd still be getting excellent DIY Articles like this:

http://www.peachparts.com/Wikka/OM606962GlowPlug

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2005 Pathfinder LE
2001 E55
1998 M3
1982 320i

So if I took some clear fuel line with fuel in it, blocked off one end, and then pulled a vacuum on the other end, I'd have a "vacuum bubble?"

I don't think so. I'd think that with that much vacuum, the line would collapse.

How about a theory that it is an air bubble under a partial vacuum?

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2005 Pathfinder LE
2001 E55
1998 M3
1982 320i

Without going into speculation as to why the bubble forms I can attest to the fact that the bubble is completely normal to find after shutdown. My car's always had one and every one I have seen also has one. Numerous posts on this board questioning the presence of the bubble confirm that it's normal...

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Still have air leaks...

Replaced those 2 lines I mentioned I would earlier.. Included are photos. The lighted lines still have air bubbles.

Attached Thumbnails

   

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#dieselFLEET
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'97 E300
'99 E300

Forgot to add that at idle there are no noticeable bubbles, but when you increase the throttle there is a surge of bubbles that come up through those 2 marked lines.

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#dieselFLEET
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'97 E300
'99 E300

Initially would brought me to the fuel lines were that when I would climb that rather steep hill near my residence the car would progressively start to buck and nail accordingly.....

Hope that helps

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#dieselFLEET
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'97 E300
'99 E300

Went back to take a look and saw that there are some still air bubbles... Photos included.

From what I can see that from seeing air bubbles in 3 lines, I'm down to 2.

I can understand seeing a few random air bubbles that need to be purged, but I can't photograph or video the little surge of air bubbles that appear when I increase the throttle...

Attached Thumbnails

     

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#dieselFLEET
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'97 E300
'99 E300

Have you replaced the o-ring on the fuel filter center hollow bolt?

It's going to wear a bit everytime you spin it when replacing the filter...

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2005 Pathfinder LE
2001 E55
1998 M3
1982 320i

I haven't replaced those in quite some time actually.... Any idea what size it is?


Anyone have a schematic of how the fuel flows through the injection system?

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#dieselFLEET
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'97 E300
'99 E300

Those are pretty small bubbles partner, and they are mostly tucked up under the insert ends of the fuel lines. It's def not a steady stream.....

I'd say let those go and drive it a while. Go charge up your hill a few times. They'll prob disappear.

If it still concerns you then follow the fuel feed path on this link and rule out supply leaks.
http://www.peachparts.com/shopforum/attachment.php?attachmentid=38226&d=1163965668

Delta - Lightman's past posts have helped me numerous times. Didnt mean my reply to sound ungrateful. The point was clarification for others who read this 5 years from now so they understand that the pre-filter line normally drains back at shutdown and don't attempt to reslove a problem that doesnt exist.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)