Was working on getting the blower to go faster than minimum speed today and had a look over the rest of the engine compartment. I noticed a bit of black stuff that looked like it was coming out of the prechamber collar ring. It was very hard and brittle; looked like melted plastic. It also looked like somebody oversprayed some black spray paint onto the underside of the intake above the injector. I chipped off the black stuff for further inspection and couldn't figure out what it was.

Drove the car around town a bit after and noticed a new sound. Took a look and found compression making its way out in the same area. I have a bunch of spare injector heat shields laying around so I decided to pull the injector and check what's going on in there. The seat and threads were a bit dirty so I cleaned it with a little diesel and a chunk of shop towel. Proper torque applied and got everything hooked back up. Leak unchanged.

Here's a youtube video where you can hear the leak around #2. In the last part I squirt some degreaser on the injector and you can clearly see compression making its way out. The cylinder still fires OK. Hope the prechamber seats aren't shot...

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Dale

http://i52.photobucket.com/albums/g1...MG_2277sig.jpg

1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

Thats a nice car. Is that the 90 300D in your sig.

Does your car still have the plastic spline shields? That might account for the the hard black plastic bits. You might get your hands on a splined socket and retorque the lock ring. What do you mean by prechamber seat?

Sixto
87 300D

The surface in the head that the tapered part of the prechamber seals against. Now that I think about it the prechambers have never been out (as far as I know) so it's probably unlikely they're bad. Don't have the splined socket. Anybody have experience with this one? It's reasonably priced and domestically available on Amazon but I'd rather pay more for a different one if it's garbage.

And yes, it is the car in the sig. The photo is at least 60k old. It needs a detail (or three) but it still looks decent and works (mostly).

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Dale

http://i52.photobucket.com/albums/g1...MG_2277sig.jpg

1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

I have that spline socket. $15 plus shipping from Amazon. It's a poor fit. I have to hammer the socket onto the lock ring so it grips, then use a breaker bar to wiggle it free.

Sixto
87 300D

Ok, I'll look elsewhere. Thanks. Did you end up getting a different one or did you just make that one work?

I removed the plastic protector and it looks like it was melting from the hot gasses leaking next to it.

Here's a photo of how it looked after a 3-4 mile warm up drive after reinstalling the injector today. The black stuff was not there before the drive. It looks like oil but I guess it could be residual spilled fuel or degreaser making its way out. The leak is definitely exiting between the head and the prechamber ring with a distinctive chuff-chuff-chuff. It still seems to fire OK and the engine does not run rough at all.

__________________
Dale

http://i52.photobucket.com/albums/g1...MG_2277sig.jpg

1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

Is this a Aftermarket Socket?

I have the real Mercedes Splined Socket and it is made by Stahlwille Tools. I have never used it so I cannot comment on the Fit. However, I can say that the cost was more than double $15.

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84 300D, 82 Volvo 244Gl Diesel

If tightening the Ring does not work there is some threads on this issue. There is an expenbsive Cutter to go down inside and resurface the Cylinder Head and a formula for which Aluminum Seal/Spacer to use when you re-install the Pre-chamber.

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84 300D, 82 Volvo 244Gl Diesel

I have the socket in the tool rental thread...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Hazet socket cost me $55 years ago it's been used a lot but still works well

Laser Tools | 5472 | Spline Socket Pre Chamber Mercedes-Benz

Sixto
87 300D

How many miles are on it? Does it have angled injection like the 190 602 does? I think my car might have a leak similar to yours.

300D 2.5 would have angled injectors. Looks to be at least 204K miles between the sig line and post #4.

Sixto
87 300D

I'm no CSI but I think oil is dripping into the injector well. If it were being pushed by compression, there'd be more of a pool in the well. I suspect it's seeping from the adjacent manifold gasket or dripping from the crossover pipe junction above.

I'd be surprised to see that much oil in the combustion chamber but 602.962 + >200K miles all too often means time for a new head gasket.

Sixto
87 300D

Was it a tight Fit like the aftermarket one mentioned?

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84 300D, 82 Volvo 244Gl Diesel