Leaking return nipple 519

knopfler

Member
Hello
Today i was changing seat sealing on injectors in my 2011 519 sprinter.

When i was done i saw that one return nipple was leaking in under around body of injector and that nipple.

Is there som way to fix that or is it only for me to order new injectors now?

I have now had this car 2 days and bougth it unseen 2000 km away from home... it was cheap.
it was a lot if carbon around injectors, and sealing was long gone... maby this return nipple also have been leaking for a while.

Victor
 

manwithgun

Unknown member
There is a tiny o-ring at the leak port that can get damaged, might want to remove the line and inspect. One of our forum members "Pneumo" discovered a damaged seal and found replacements. Are you sure you seated it properly? There should be a positive "click/snap" felt while pushing them down before you lock the ring.
 

knopfler

Member
Its not from sealing, its under that nipple into that plastic/composit. Locks like a small crack into steel nipple
 

manwithgun

Unknown member
In that case the injector should be replaced, which must also be mated to your ecm with a capable scanner. Every injector has an alphanumeric code, representing its calibration, and needs to be assigned to its cylinder position. In an emergency, I suppose you could attempt a field repair by degreasing and sealing with an epoxy? Not sure if something like JB Weld is chemical/heat resistant enough but it may serve as a band-aid. :idunno:
 

knopfler

Member
In that case the injector should be replaced, which must also be mated to your ecm with a capable scanner. Every injector has an alphanumeric code, representing its calibration, and needs to be assigned to its cylinder position. In an emergency, I suppose you could attempt a field repair by degreasing and sealing with an epoxy? Not sure if something like JB Weld is chemical/heat resistant enough but it may serve as a band-aid. :idunno:
I have a friend with blown engine from 518, i will pick up one of his injector and try try take it apart and se if i can get that nipple loose and reuse it on my injector. If not i will try with plastic glue from 3M. They have a heavy glue that melt into plastic. I think its not so mutch pressure on returne line...

I also need to finde new return line now, this plastic **** its bad on mercedes... every mercedes with plastic on fuelsystem i have working on its same crap
 

lindenengineering

Well-known member
A few note from Ratchet & Wrench.

That leak off nipple is a part & partial of the injector.
Being delicate you have to be careful when removing injector pipes since there is little room for angular movement using a normal line wrench or spanner. Indeed even removing the leak off rail connector socket can cause damage if you are clumsy. There are two versions of that connector.

As usual there is a special tool for that, https://store.snapon.com/Flank-Driv...-Drive-Flare-Nut-Crowfoot-Wrench-P644075.aspx

(so there is little chance or bending nipple and causing it to either crack or start to deform where it is fused at the injector body when using this tool.

Its a crap shoot whether you will seal it using some form of "gobwhack" .

The tip has an O ring as mentioned.
You can get these under an MB or Bosch part number. Here in the USA they are 0,30 each retail.

Do not try to dismantle the piezo style fuel injector, it will be scrap once you do!

Yes MB and in fact many Euro based vehicles have delicate connectors from a professional workshop perspective . Its their Achilles heal with faults and repairs in many cases.
Consequently its prudent to keep many replacement new connectors for harness repairs in stock . MB seems to recognize that fact,. as most connectors are available as individual parts with exception of the MIL diagnostic connector for some reason.
By comparison Ford harnesses & connectors being ISO 9000 complaint have the best, but Toyota/Lexus can be argued as better. Boiled down its individuals' brand preferences.
All the best with your DIYing
Dennis
 

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