Help: injector / prechamber / heatshield leak
 

:computer: :computer: :computer: :computer:

I have 1989 190D 2.5. it has a leakage between head and prechamber holder ring (not the injector and prechamber ) I have searched and searched and searched and could not find an answer. So please help me.
:confused: )I took an injector out to replace heat shield washer. it looked like prechamber holder ring was holding it. after doing some reading it looks like it is the carbon deposit that was holding it too tight. i will give it a try tommarow again. now after putting it back toghether i am getting a hammer like nailing/ ping/ knock noise. Have i damaged something?? or is it beacause its leaking compression more than before now??
:confused: second question is can i knock out the heatshield washer using a punch and hammer ?? or is there any other method to take it out??

:confused: Is the leaking because of the bad heat shield ?? bad prechamber?? from the dieagram here
http://skinnerbox.steaky.org/Service/W123/w123CD2/Program/Engine/615/07-230.pdf
it looks like bad heat shield should not cause leakage between the ring and head. what do you think???
i appreciate your help.

I have removed and replaced these shields on a 220D, and twice on 240Ds. I used a tool with a what is easiest to describe as a small threaded strawberry on the end of a screwdriver from Sears. I jammed the tapered threaded thing into the center hole and turned it. It got a grip and I just gave a slight tug and the shield came right out. It worked on the two different designs of shields.

If you examine the cross section view of the parts in your link, you will see the heat shield is squeezed between the injector nozzle face and the prechamber. There are no soft gaskets between the injector and the prechamber, and there is certainly no thread sealant. As a result, I believe that by design the heat shield is used to form a seal between the nozzle face and the prechamber. If you have damaged this by deforming the shield, it is feasible the seal will no longer exist and exhaust gas pressure will force its way out past the threads of the injector to the prechamber. Once pressure gets there it can work its way out between the locking collar and the injector or, if something is blocking that path, between the collar and the prechamber and out between the collar and the head. Jim

Thank you very much for the reply. I am going to change the seal thing first thing in the morning and see how it goes.
Just in case If it wont solve it i have already oredered the prechamber ring tool from merecedes and from reading the forums it looks this tool (links) will do the prechamber pull job.
thanks again.

http://yuyama.dip.jp/pics/crank3.jpg
http://bike.shimano.com/catalog/cycle/products/multiproduct.jsp?FOLDER%3C%3Efolder_id=2534374302032746&ASSORTMENT%3C%3East_id=1408474395181202&bmUI D=1113534397719

Update
 

I pulled the injector and replaced the heat shield from cylinder one. Did not stop leaking. Then i ordered the prechamber ring socket. It came all the way from Germany to canada , took 1 week. Today i pulled injector # 1 out. Took the ring off from cylinder # 1. Tried to pull prechamber out with slider hammer and the this thing that did fit in the threads. after about 10 tried the adapter thing broke. Then i just cleaned it and put is back together. Looked like its not leaking as much. So i decided to do the same on cylinder # 2.
I took injector out and guess what ?? the heat shield decided not to come out.
i started torturing it. did beat it center punch, screw driver, and hammer. I hope it was heat shield , not the prechamber itself. anyways after struggling 2 hours i gave up. i sprayed wd-40 and will give it a try after day or so. it looked damaged prety bad.


On these newer 602 the setup is different. injector threads, heatshied seat and whole thing is built in the prechamber. The ring only holds the prechamber in place.

Can anybody help me with pulling the prechamber out? does anybody know if there is anything that has same threads as injector that i can use as a puller??
Can anybody help me with removing the stubborn heat shield?? any suggestion.
I appreciate your help.

seal woes
 

I HAD A similar leak in my 90 350sdl. it turned out the injector seal was missing. it is a little steel ring thing. looks like a button with one hole sort of. it is something which could fall off the end of the injector i believe. if missing will cause leaks or also affect the injector spray pattern in the combustion chamber causing excessive diesel knock. on my car all six had been left out. it was running poorly, smoking some and had such a loud knock that you would swear something mechanical was about to break. if this is missing it could be a simple fix... which usually is the case with benzes although sometimes hard to track down.

looks like i had the seal. I tried to take it out but the carbon was holding it too tight. i think when i started beating it, i think it expanded and now it wont come out, unless somebody has an idea???

Now if it wont come out will i have to replace prechamber???

replace pre...
 

now you're beyond my experience... sorry.

thanks anyways T.
i took it out with some wd40 and some more beating. i did damage the prechamber seat. i can see the cut. i put a new seal and its not leaking between the prechamber and injector. so i think i am safe for now.
iwill be pulling the prechamber soon , once imake the tool to pull it out

And finally leak is fixed
 

finally i took out the prechamber, cleaned it and put it back in. No more leaking.
anybody who has the similar problem can contact me for any help, howere i will not be responsible for anykind of damage. i can share my experience.

To those who might be curious about these newer engines.
prechamber is one piece thing. thre ring is just a ring to hold the pm in place. injector screws in in thre PM itself.

the prechamber / injector threads are same as on the dodge caravan axle shaft. i used an axle shaft outer piece with slide hammer to pull PM out.
i think the threads on saab, mazda 626, nissan pulsar axle (possibly some honda's) are also same.

thank you everybody who helped and tried to help me.

a1jatt
a1jatt at yahoo dot com

Someone referenced this post in another link.

What I discovered inadvertently is that if you crank the engine with the injectors out, compression will likely cough out the injector shields.

Sixto
93 300SD

not on the 79 617 I worked on.
 

some of the shields came out, but one of them was so carboned up, it took hours with a dental pic to get it clear... man what a mess a poorly installed injector will do!
however, once cleaned up (lots of pb blaster and a shop vac) and installed PROPERLY, the 617 sure does purrr!
John