I have replaced the return lines, with clear lines and no bubbles are escaping, I cleaned the head and side of the block with degreaser and washed it well. after about a 15 minute drive the engine warms up nicely, but there is diesel leaking around the injectors at the head. it looks to be leaking from the semicircular "prechamber"? it is the part that actually screws into the head. not the part where the injectors actually screw in. is there a special tool to tighten this part? do the injectors need to be removed? instructions and a tool list would be very helpfull. Thanks!
John

There is a special tool needed to remove/tighten the prechamber ring. Be certain that fuel isn't oozing from the return lines, it can be misleading. Yes, if it is leaking around the pre-chamber ring on the outside then you have to remove the injectors; I know what the tool looks like and I believe the injectors would be in the way. If one or more seems to be leaking it does sound more like the return lines are leaking. With a cold engine you could try spraying a little soapy water around the ring; if they're leaking you'll see bubbles.

Is there a reason to use other than the factory tubing for the return lines?

My 81 300SD was doing the exact same thing. I fixed it by removing the injectors and replacing the metal washers under them called heat sheilds. Notice the direction the old washers are facing as they are made to go one way and not the other. This should stop the leak! Good luck!

Under the injectors there is a copper washer. Maybe it bronze but either way if they've become loose at some point they'll melt or deteriorate. The injectors have to be removed to replace these washers.

I only mention this because it seems to be a diesel engine thing and not just a MB engine thing.

Wayne

I couldn't find a shop that supplies the correct return lines. none would sell a fuel line smaller than 5/16" but the leak was pretty bad, so I kept looking and found the lawnmower fuel line perfect, and it is clear to see any bubbles in them! kinda looks like those bling bling cars neon kits added to my motor! anyway, the bubbles are coming from the rings and I am pretty sure I gotta tighten them.
John

Lawnmower line won't last long.

You can get proper injector return hose from a VW dealer.

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i bet your leak is from the return lines.

ditch those clear plastic jobbers! and get some factory line. it doesnt cost much even at the dealer.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I live in a pretty rural area, and work full time, so getting into Charlotte during the week to buy parts from the dealer involves taking a vacation day. I suppose I could mail order the hose from somewhere. Dieselgiant you got any? I called the charlotte import dealer, and they have hose, but they want 10.00/foot... kinda high in my opinion...
I still don't know where to get a tool to tighten the rings around the injectors. no the injectors themselves are dry no fuel on them at all. and bubbles are coming up from the rings themselves.
John

$10/foot is indeed too much. It should be about $10/meter or so, and one meter should be enough to do the job.

I bet Fastlane stocks the stuff.

I also agree that your problem is the return lines. I just replaced mine this week after noticing leaking diesel at the injectors. I ordered the fuel line from fastlane and received it two days later. Make sure that you also order the end injection plug (and maybe also a spare), as that was where I was leaking most of my fuel.

really, there is NO fuel on the injector bodies, just bubbling visibly up from the rings around the injectors... I mean I can SEE the bubbles on the rings.
at this moment the return lines are not leaking. I will try to find the correct return lines, but that is NOT where the leak is coming from.
actual bubbles and fuel eminating from the rings.
I need to know what tool to use to tighten them.
thanks very much for responses, I hope to solve this soon.
John

Do a search on "mercedes pre-chamber removal installation tool".

http://www.samstagsales.com/mercedes.htm#trunk

search for this part # tools needed below great find!
001 589 65 09 00
but 50.00? wow
also the "correct" socket for removing injectors 27MM with knockouts for the return lines another 50.00
thanks to all for replies and help!
John

same line still not leaking on my car... that's what 4 years?
um, sounds like I have successfully found a decent solution to the return line melting issue every 2 or so years. and they are clear and you can see bubbles etc.

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