Diesel injector blowing smoke? W210 E 320 CDI

[faz2704]

Hello people,

Yesterday I noticed my E320 CDI engine sounded tired and lazy similar to a none working piston type noice. I popped the hood whilst the engine was running to find smoke (not steam) rising from under the plastic engine cover ....I switched the endine of and stared at it for a moment feeling unsure and rather lost as to what this smoke means.
I removed the plastic engine cover and so signs of oil and black smoke as well as some hardened black stuff :s ....I cjhecked the wires leading to the injectors and they all looked and felt ok - not burnt.

I then started the engine and found blue smoke blowing out from number 3 injector! Confused and concerned I looked closer and found the the bolt which holds the injector in place was loose, I tightened it and started the engine, it sounded normal and no more smoke from the injector

MY QUESTION:
I took pictures showing the area arround the injector which are attached here.

What is all the hardened black stuff and how do I clean it of?

Thank you very much.

 

[Cole@MBS]

It takes a lot of cleaning by hand, injector out, seat needs re-cutting along with the injector, Dave and i had to do 2 of them at the start of the week, New bolt and washer as well!!!

 

[Parrot of Doom]

Soak the crud in diesel for a few days. It'll shift, although you may have to whack it a few times with something sharp. Be careful you don't damage anything.

Or you could just leave it there - it won't do any harm.

 

[exeng]

If it has been leaking you will need to remove injector and replace sealing washer and bolt soon as it will most likely start to blow past again but try to remove as much of the black death as you can as you dont want it down the injector hole

 

[faz2704]

Thanks for the replies.

The black stuff has hardenend on one of the injector torque bolts now I can't open that bolt.

I won't be bying Mercs in the future, 1 problem after another....total CR*P

 

[exeng]

Soak it in good old coke or mr muscle oven cleaner be carefull with the later also once clean try to remove when engine is hot as if carbon has got down the bolt hole they can snap when you try to remove them once removed you will have to clean the threads and injector seats to ensure correct torque seals the injector

 

[Jonski]

E320CDI Blowing Injector

I also have a blowing injector (I was just planning to fix the glow-plugs until I took the lid off and saw the mess!), the car has only covered 75k so I was surprised...Judging from the amount of black Crud I cleaned off, its been blowing a long time. I can't see items like a replacement injector bolt and copper washer on EuroCarParts, so I wonder if someone can tell me where I can mail order these? thanks...

 

[Silver_Star]

You can get them for very little from any MB dealer.

You will need a new washer for the bottom of the injector and a new bolt and clamp for the injector.

As mentioned above it is advised to recut the surface where the washer and injector sit. Also thoroughly clean the threads of the hole the clamp bolt fits in.

 

[Jonski]

Thanks for your reply. I don't have much in the way of tools, but I saw elsewhere on the forum, two suggestions for re-cutting the injector seat :

1. - Use Valve grinding paste, with the existing injector as the grinding tool.
2. - or, use a valve grinding stick with emery cloth glued on.

No.1 sounds good to me, do you have an opinion on these please?
also, what could I use to clean out the thread of the bolt hole?

 

[Silver_Star]

If it were me doing it I would not consider either of the above and only use the proper tool. Do it once properly else it will only come back to haunt you. You may be able to borrow one from a local garage or somebody on here?

You should be able to clean the thread with a tap.

 

[Jonski]

Thanks again. One more question on that please , excuse my lack of knowledge, but whats the correct name for the proper tool?

 

[Cole@MBS]

There is a tool for re-cutting the seat, not sure if it has a "correct" name!

 

[Jonski]

E320CDI Blowing Injector

- Thanks to all for their help and advice, which has allowed me to get this job done. I therefore wanted add my experience of fixing a blowing injector on my Yr. 2000 W210 E320CDI (75,000 miles) to the body of knowledge on this forum, in the hope it might help someone else :

- I took off the engine cover to replace a glow plug and noticed that No. 1 injector was completely caked in shiny black stuff. At first, I thought it was some kind of sealant. In fact it was a carbon deposit which gradually builds up around an injector which is leaking exhaust gases. There was a loud ‘chuffing’ sound and I could feel the gas blowing out on my hand each time No. 1 cylinder fired.

- I cleared the black stuff off using various screwdrivers and knives. Chipping it away bit by bit. I adapted our hoover by taping a thinner metal tube onto the end and periodically cleared away the debris.

- There is a single bolt which holds the injector down via a clamp. I sprayed some WD40 around this (having ensured that all the black stuff was cleared from the joint). I then succeeded to undo the bolt a couple of turns without breaking it (apparently a significant risk).

- The injector was clearly ‘welded’ into the engine by the black stuff. So, leaving the bolt undone a couple of threads, I started the engine, and started (carefully) hitting the top of the injector where it looked the most solid with a hammer and drift, I tried to hit from both sides. It didn’t seem to be moving at all, but when I turned the engine off, it had moved up 1 mm or so and the clamp was pressing up against the bolt.

- Encouraged by this, I removed the bolt and started levering the injector from side-to-side using a large chisel (carefully) against the fuel inlet part of the injector. It gradually got looser until I could turn it back and forward by hand. I then worked it back and forward, pulling up at the same time, until it came out. I hoovered around afterwards to minimise the amount of remaining black debris and dust falling down the injector hole (and the bolt hole).

- Then I made a mistake, I tried to run my new bolt (bought from Mercedes) to the bottom of the bolt hole, it came up a bit tight, and instead of taking it out and checking the hole for debris, I continued tightening a bit, and this resulted in stripping the first 3 threads out of the alloy cylinder head. I then took the bolt out and tried to clean out as much debris as I could with a screwdriver, then I further adapted my hoover, taping a drinking straw on the end, and I used this to suck out any remaining debris and WD40 which had found its way down the bolt hole.

- I still had trouble getting the new bolt to go far enough in. The Mercedes bolt has some yellow stuff on it about halfway up (some kind of torque-seal I assume). I wondered if this was fouling up with the black carbon deposit which was certainly coating the interior thread, so I scraped most of it off. A bit more hoovering out of the hole, and finally the bolt went in far enough to clamp the injector firmly down, even without the copper sealing washer in place, so I figured that would be ok.

- I cleaned all around the injector itself with a stanley knife. Keeping clear of the injector tip.

- I don’t have a refacing tool, either for the injector or the injector seat, and I didn’t fancy buying one - there seems to be a certain amount of feedback on forums that using these can sometimes result in bigger problems. I therefore decided to take a chance (supposing that the worse that could happen would be that I need to remove the injector again which, second time round, should be easy). So, I cleaned the face on the injector with a stanley knife, and I cleaned the face at the bottom of the hole using a long screwdriver, hoovering out regularly, until it looked nice and clean.

- I then sprayed WD40 into the inlet of the injector itself, whilst holding upside down to flush out any bits of dust which might have got in.

- I then fitted the special Mercedes injector copper sealing washer, bought from Mercedes together with the bolt for less than £3, and tightened it down. I don’t have a torque wrench, so I used a 6 inch adjustable spanner. The short length of spanner and the fact that it tends to slip round limiting how tight I could get it (but also limiting the risk of stripping more thread or breaking the bolt). I then ran the engine for about 15 minutes at tickover, and no leak. Afterwards I again tightened down the bolt on the now warmed up sealing washer. Later I took the car for a short run. Afterwards, when I checked injector with the engine running, I could see a few bubbles coming out in the WD40 which was still around. So I got some mole grips clamped onto my Torx drive to get a bit more leverage. I tightened the bolt a bit further an the bubbles reduced but did not stop completely. I didn’t like the ‘feel’ of the way the bolt was tightening – I had the impression it was turning but not getting any tighter, (i.e. bolt stretching) so I didn’t dare tighten any further. I then took the Car for a 100 mile round trip and checked later by pouring some water around the injector with the engine running. No Bubbles, so I believe the copper washer had bedded-in and sealed up the injector.

- I had also been advised to replace the injector clamp. The Mercedes garage told me, rightly or wrongly, that I would be wasting my money to replace this part. I may be wrong but, having done the job, I also can’t see why this would be necessary.

- So, that’s how I did the job using a minimum of specialist tools. Took a few risks which could have turned out as expensive mistakes I admit.

If the engine starts blowing again in a few days/weeks then I’ll update this thread.

 

[EuroCLK320]

Did you use any 'special grease' when you put the injector back in?

As for the bolt 'stretching' I think it may be designed to do that.

Hope thats the end of your troubles anyway.

 

[Jonski]

No, no special grease used. The injector bolt bought from Mercedes has a patch of yellow stuff on them about half way up the thread, not sure if this is torque-seal or some kind of grease..

 

[Jonski]

Having said that, I did put a little Castrol LM grease on the copper washer to stop it falling off the injector as I lowered it back into the engine.

 

[Jonski]

Blowing Injector

I had the engine cover off to replace a couple of glow-plugs. No sign of any leakage from the injector to date...

 

[Jonski]

Still no visible sign of any Leakage.

Still no visible sign of any Leakage.

 

[Alex Crow]

well that is good, thanks for the update.

well that is good, thanks for the update.

 

[Jonski]

40,000 miles on...update....

The repaired injector is now, once again, leaking and showing some carbon build-up. A minor leak I would say, as I can't hear or detect any gas escaping.