Is this a prechamber leak? Pictures - PeachParts Mercedes-Benz Forum

bgkast · #1 12-30-2005, 05:12 PM

I have bubbling and wetness around the base one injector on my new 240D. The bubbling looks to be coming from between the prechamber and the head. Could the fluid coming from this leak, or do I have a separate fuel leak too?What should be done to correct this problem? Thank you. -Bryan

whunter · #2 12-30-2005, 06:12 PM

Quote:

Originally Posted by bgkast

I have bubbling and wetness around the base one injector on my new 240D. The bubbling looks to be coming from between the prechamber and the head. Could the fluid coming from this leak, or do I have a separate fuel leak too?What should be done to correct this problem? Thank you. -Bryan

Replace the two fuel bypass hoses on that injector, then clean the affected area (COLD) with carb/choke spray.
Warmup the engine, and inspect for leaks.

bgkast · #3 12-30-2005, 08:13 PM

I'll Give that a try tomorrow and report back. The bubbling looked to be coming from the area between the prechamber and the head though. Would leaking bypass hoses cause a similar look? Thanks very much for your help. -Bryan

#4 12-30-2005, 08:17 PM

Quote:

Originally Posted by bgkast

I'll Give that a try tomorrow and report back. The bubbling looked to be coming from the area between the prechamber and the head though. Would leaking bypass hoses cause a similar look? Thanks very much for your help. -Bryan

It's too hard to tell until you get it cleaned up. My bypass hoses were leaking when I first got my 300D and I had fuel everyplace. It also made the whole car smell like diesel.

84300DT · #5 12-30-2005, 08:55 PM

Quote:

Originally Posted by bgkast

I'll Give that a try tomorrow and report back. The bubbling looked to be coming from the area between the prechamber and the head though. Would leaking bypass hoses cause a similar look? Thanks very much for your help. -Bryan

my no5 injector looked the same- replaced the stubby line on the end
and the 'leak' stopped. i also thought the injector was leaking but it turned out
to be the braided line. that would be the first course of action in my opinion.

bgkast · #6 12-31-2005, 03:54 AM

The thing that concerns me is the bubbles seem to be coming from a compression leak. You can see a few bubbles in the picture right by the tip of the arrow (the car was running when the picture was taken). If I fix the fuel leak I still think that there will be a compression leak, you just wont be able to see it any more. Could a leaking return line cause bubbles in the area around the pre-chamber?

If it is a pre-chamber leak would it be less expensive to buy the specialized tools to remove the pre-chamber or take it to a mechanic to re-seat it?

Thanks again. -Bryan

whunter · #7 12-31-2005, 11:22 AM

Quote:

Originally Posted by bgkast

The thing that concerns me is the bubbles seem to be coming from a compression leak. You can see a few bubbles in the picture right by the tip of the arrow (the car was running when the picture was taken). If I fix the fuel leak I still think that there will be a compression leak, you just wont be able to see it any more. Could a leaking return line cause bubbles in the area around the pre-chamber?

If it is a pre-chamber leak would it be less expensive to buy the specialized tools to remove the pre-chamber or take it to a mechanic to re-seat it?

Thanks again. -Bryan

Hope this does not sound grouchie, darn flue bug got me.
Do not assume.
Fix issue #1 = the fuel leak.
This should take only a few minutes, clean (COLD) and test.
When you have confirmed the leak has stopped, then go on to other issues.

When I see bubbles in that area, 99.99% of the time it is the bypass hoses leaking.

84300DT · #8 12-31-2005, 01:57 PM

it should be mentioned to use OEM bypass line - i have found using other types they have leaked .. i got some from the stealer at (ahem..) an inflated

price but at least it works and lasts.

bgkast · #9 12-31-2005, 07:06 PM

Well new lines seem to have stopped the fuel leak, but I put a drop of oil where the bubbles were coming from and it still seems to be leaking compression. What should the next step be, replace the heat shield under the injector? I was hoping I could drive this car 300 miles back to college in a week, but I don't think that I can get parts here quickly enough to fix it. Will it be ok to drive it with a small compression leak?

Hope you feel better whunter.

Thanks. -Bryan

Hatterasguy · #10 12-31-2005, 07:17 PM

A few bubbles their won't bother anything. If it really bothers you find a pre chamber socket and replace the pre chamber. If you are going through that you might as well send your injectors out to be tested while you are at it.

bgkast · #11 12-31-2005, 07:46 PM

OK. Thanks. Is it possible that the leak is being caused by the heat shield as suggested in the second post of this thread: Help: injector / prechamber / heatshield leak

Thanks again -Bryan

Hatterasguy · #12 12-31-2005, 07:54 PM

Probably not, are the bubbles coming from the base of the injector or where the pre chamber meets the head?

I am not really familer with the 616, but on the later MB diesels their are seal rings that help seal the pre chambers. I would suspect those seal rings.

bgkast · #13 12-31-2005, 08:01 PM

It is coming from between the prechamber collar and the head. From looking at the diagram that is linked from that post it looks as if the heat shield were leaking the compression could leak past the threads on the prechamber collar. I guess I will drive it back to school and maybe try replacing the heat shield before I pull the whole prechamber. -Bryan

duxthe1 · #14 12-31-2005, 08:21 PM

Unless you are an anal perfectionist, I wouldn't even screw with it. Not gonna hurt a thing to leak a tiny bit. I would suspect that as the engine is revved it will actiually slow to almost stop the leak. As rpm rises the pressure cycle becomes shorter in duration and there is effectivley less time to leak. So in essence the very minor problem becomes even less so as you drive.

Ralph69220d · #15 12-31-2005, 11:28 PM

I agree with the other forum members. It sure appears from the picture you posted that the pressure is leaking from the prechamber and/or burned/leaky heat shields. I would say that if the heat shields are old and someone didn't tighten the injectors to the proper torque, those heat shields will burn fast causing the problem you're addressing. The pre-chambers may be cracked, a lot more costly than merely replacing the heat shields, but I would think it adviseable that if you have injectors out and have the tool to remove the prechambers, pull all of them and closely inspect for cracks. There is a substance than can be applied to the pre-chambers that will show cracks not visible to the naked eye. I know another forum member posted on that substance in another thread, so you can do a search on it. If anyone ever used ether to start the car the pre-chambers really see some pressures they should never see. Best wishes.