240D Pre Combustion Chambers Leak

[230CE1984WP]

I have a 1977 ,240D 123.123 - I had purchased a month ago when weather was cooler/cold.
Now that it is warmer i noticed a couple of the pre-combustion chambers are leaking/bubling where the chamber meet the cylinder head.I purchased a service manual and it shows "seal rings " seal this chamber to the head.
My question is - is it ok to change the seals only(i would do all four) or do i have to replace the pre combustion chambers as well(the injectors seal within this chamber held down by a threaded nut?
Am hoping i only have to change the seal rings as the "pre combustion chambers are pricey and have to be a special order .
From the "cold north" in Ontario Canada.
Thanks
Other than the above small problem it sure is a "hoot "driving this 31 year old 4 speed manual around town.

[Diesel911]

What is it that is bubbeling up from the pre-combustion chamber ring? If it is it Fuel or???
You need a special tool to remove the pre-combustion chamber ring. To change seals you will need to remove the fuel injectors the heat shield at the bottom of the injectors (wich you throw away and replace with new ones); next you use the tool to remove the pre-combustion chamber rings.

[carnut]

Clean the area with carb cleaner or brakekleen then start the car and report back. Somewhat rare to leak there. More likely oil residue or seeping fabric transfer hoses dribbling down the injector settling there.

[Marty600]

If it is a prechamber leak, you will hear it. I had one. You can also see the sooty
material around the injector, at it's base.

[230CE1984WP]

I have replaced the fuel leak off hoses , connecting all the injectors- they were leaking as well. All is good there now.
I believe it is oil that is leaking - you can actually see the bubling/leak as the engine is running - i think that would be the compression from the engine that i see bubbling - it is not audible-is not that bad a leak- however the leaking is causing the dripping fluid to smoke as the engine heats up.
I believe the leak is not the injectors or between the injectors and per-combustion chamber - I think the leak is on the outer side of the precombustion chamber?

[Diesel911]

I have to agree with the other 2 members. When the fuel starts to burn there is thousands of pounds of pressure, If there was even a tiny leak the combustion gases would come out.
When the engine is hot the bubbling could be the oil be evaporated slowly by the heat. [This is just my thought on the bubbling if it is happening when the engine is cold. I think it is possible for the vibration/shockwave created by the burning fuel to cause that bubbling. If you put a glass of water on something that is vibrating it moves the fluid around. I have no proof of this. But that is my thought.]
In any event if your engine is running good. I would just clean the oil out as the other member said; drive the car and as long as the car performs OK I would continue to drive it.
If at a later time you pull your injectors and you want to change the pre-combustion chamber seals that would be a good time to do it.
By the way did you look up the tools needed for the job?

[230CE1984WP]

No - did not check tool requirements yet - want to make sure I know what is wrong first-
The leaking/smoke although small is too bad to continue driving as such-i have cleaned this up but comes back quickly -
Is there a chance that the injector seals(heat shields) could be leaking fuel from "inside" the chamber -and the actual leak is between the injector and the pre combustion chamber?
Thanks

[bgkast]

My first 240D had the same problem, I just ignored it as it seemed to have no effect on the engines compression.

[winmutt]

You say the fuel is bubbling up from the injectors? Or is that bubbles are coming up where fuel has spilled? If its fuel coming up then you have a leaky injector. If its gases coming up you probably have a burned seal.

The prechamber lock ring tool can be bought for $70 or so from pelican parts. The prechamber tool it self can be made from 22mmx1 bolt from a Shimano bicycle crank puller $17. You will need a slide hammer as well. I recommend replacing the prechamber ring (dont forget your heat shields as well) as it gives you a great chance inspect the prechamber for cracks and what not. Injectors and prechambers ARE wear items.

[Diesel911]

Originally Posted by 230CE1984WP

No - did not check tool requirements yet - want to make sure I know what is wrong first-
The leaking/smoke although small is too bad to continue driving as such-i have cleaned this up but comes back quickly -
Is there a chance that the injector seals(heat shields) could be leaking fuel from "inside" the chamber -and the actual leak is between the injector and the pre combustion chamber?
Thanks

I am thinking that if you fix the leak and clean everything off well the smoke will go away.
It is possible for the heat shelds to leak if they have been installed upside down or have been reused (you are supposed to replace them ever time you pull the injectors out), not tightened properly, or the holes not cleaned before the new heat shield goes in.
In the past I have reused the heat shields (they are the same) on my Volvo diesel as back in 1996 I was not on the internet and did not know that they needed to be changed everytime you pulled the injectors. I never had a problem with leaks in that area.

[Marty600]

if you have changes your return lines, but you still see 'bubbling', it is time for an injector rebuild, the fuel is leaking out of the 'body'. Again, the prechamber leak will produce a "phhhht phhht" noise, every cylinder discharge will push a teeny amount of hot air out...now, I don;t know, but maybe you have a leaky heat shield causing this.
But a bad heat shield will not produce visable bubbling, it will allow a slow but steady
accumulation of unburnt combustion products (read: black tarry deposits).
Diesel giant has bosio nozzles and a good WWW site for you to save $$$$ and do it yourself, I did, it was actually fun and not difficult. You need to,as the germans say, 'dress" the mating surfaces after you take the injector apart. dress is another word for 'stone' or 'lap'. I have a machine shop, so i could deal with that, but it needs to be done. Find a truck service center, they do it every day.
Here in chicagoland, "midwest fuel injecton" can balance, pop test, and dress your injectors. I think they are nationwide....Good luck, marty

[Oracle12345]

I have the same issue at number 3 injector. Fuel is bubbling up. However I changed the heat shield, swapped in non leaking injectors and still fuel bubbles up. It is possible I have all leaking injectors but doesnt expalin why they began leaking now when they werent leaking before.

[Goatman]

Happened to one of my pre's on my SDL. I changed it out, along with a new seal and it's been disco ever since.