Crystalized / Black Death

I would not immersion clean the injectors unless you put an air tight plug on the return and supply lines. Any contamination inside the injector can destroy it. Personally I would clean externally by hand only.

Also, I would not touch the glow plugs at the same time as the injectors. Get the black good cleaned up, and the injectors back in. Once its running and everything seals. Then you can tackl the glow plugs.
10-4 on the immersion

So at this point i am going to pull the keepers in the injectors and start cleaning deeper. I have hand full of plugs I could jam in the hole so nothing sneaks inside . Going to order that Carbon-off product by discovery

I was also planing to do all 5 injectors because that’s is how I do thing unless that is over kill and I only do the one is leaking .. Any thought on that
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2004 140” HRC 2500 (Crewed)
Keep in mind that you will want the engine HOT when you remove the injectors. It helps if you have a good steep hill near by to drive up?

There will be tar filling the clearance of each injector, and they’ll be held tight.
Consider removing them one at a time, cleaning, and replacing before heating up again and tackling the next injector.
The engine is likely to cool enough that the tar will begin to grab before you can start the second injector.

There’s also the “one turn loose” drive-and-pop method of removal, slide hammers, and as a final resort pullers that require opening the top of the injector (which commits you to having it rebuilt)

Good luck! Slow and steady forward :thumbup:

Can I pull them all at once ?

Is the best practice to redo them all or The leaky one ONLY . ?

I am buying a kit from that has all new 5 bolts , copper washer and o ring

Also what is the torque spec on the keeper bolt

Patrick of M

2005 T1N 2500 (NA spec)
ALL at once is read what Dave said. The T1N engine cools down fast, get it hot, pop heat and pop the next,,etc etc. Inefficient perhaps but not as inefficient as breaking stuff during removal.
I suggest reading the injector replacement and black death threads in detail. You will get all the info you need, and there are numerous minor details that you need to get right.
Are you referring to this thread

Also what is your thought on Honda Washer / bolts ? As I came across a thread stating that they will be less likely to leak
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'05 Snow Camper, '17 170 4x4, Adventure Vissionary
Lots of threads on how to successfully do this job, but you may want to pay close attention to:

+ not breaking the hold down bolt on removal
+ properly cleaning and adding structure to the injector bore seat surface
+ properly cleaning (including deposits at the bottom) and retapping (not necessarily a full retap, but making sure the threads are squeaky clean by running at the very least another bolt through it which is cut to act as a tap) the injector hold dow bolt bore

Mbz o rings are fine.. they are convex and need to be properly placed..

Lots of other little tricks, but that’s the nuts and bolts of the job :))
I pulled all fwd 4 injectors at one shot. When the Eng block started to cool I used heat gun + PB to the body of the stubborn injector to easy it out and i took advantage of the twist back and forth pull motion to aid, heat was enough but at short intervals to protect the harness . #5 is playing hard to get game . But tomorrow is another day. 4 out of 5 i say that is the luckiest i ever been.


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enthusiastic t1n packrat
Twist method usually works. Sometimes it can take a very long time, but usually if they'll turn they'll eventually come out.

I still swear by carbon off and spraying it off with the injectors still in the head so water doesn't get into the cylinders. Carbon off melts that crystalized carbon.

I know it says apply cold, but I've applied carbon off to a hot motor, just don't inhale it, you'll regret it. Also don't get it on your skin, really hurts.
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I actually twisted one out of the 4 , I ran the van until it warmed up , i have been working in that area for the last 2 day, been spraying w EGR cleaner that i had on the self which has been eating that carbon and transforming it into sludge , after the ENG reached a decent temp, i started loosing the keepers bolt and 3 out of 5 started popping and steaming ready to be removed , the #1 was the one i had to twist , there was so much junk all over it, #5 is no go yet .

I just ordered 'Carbon-off' but in the mean time i am going to clean the injectors , work on #5 , I am not a fan of water other than depressing /rinsing the eng to chase a leak , i have been using HP air nozzle and modified shop vac hose to pull the loose stuff
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Spent a decent time cleaning and cleaning more , Today the carbon off arrived so I applied it and watched the magic . That stuff really works , #3 the one caused all that nasty mess comes to find the seat was lightly scored , resurfaced . I will go over all of them again with valve lapping compound to smooth the seat .

Used the old keeper bolt and made a chaser to clean the thread ,it worked pretty well .


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Went to local Hardware store and found hallow with thread busing plug 5/8” under 15mm just fits perfect below the bore lip , plug is guaranty seal to no trash will go in during cleaning , I also stuffed paper towel soaked w PB as insurance policy .

Here is the bore before and after


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2004 140” HRC 2500 (Crewed)
Re lapping the seat: I’m a proponent of final surfacing with a dowel tipped with coarser emery (I used 150 grit). This leaves concentric tracks on the surface for the copper to deform into and get a better seal. The factory surface was stamped with a rough tear-drop pattern; shiny smooth is not what you want.


Added: factory tear-drop pattern:


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Engineer In Residence
I tend to agree. No finer than 200 grit. I would say even 80 grit is okay, as long as the scratch pattern is circular. The experience on the forum indicates that many (most?) leaks tend to erode the copper seal more than the seat. My opinion is that water in the bore causes corrosion, resulting in a leak. I would suggest coating the injector body with zinc cold galvanizing paint (basically fine powered zinc). This will be sacrificial, protecting everything in the bore for some time.
What every one use to coat the injector bodies before they slide in the bore, in the past i have always used thin coat of Permatex anti seize on all my diesel injectors and marine engines with great success .

I also like to confirm the torque on the keeper bolt it shows 62in-lb + 90° which mean it is only 5.16 LB of torque ? That is lighter than torquing A valve cover :hmmm:

Final finish on the cleaning process.


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UK 2004 T1N 313CDi
I also like to confirm the torque on the keeper bolt it shows 62in-lb + 90° which mean it is only 5.16 LB of torque ? That is lighter than torquing A valve cover :hmmm:
But then the + 90° turn puts the bolt into yield.

PS Some manuals say + 90° then + 90° again (ie + 180°). I'm not sure which is correct.


Aqua Puttana

Poly - Thread Finder
... I'm not sure which is correct.

I'm not either, but 90 degrees seems sufficient.

Here at the Global Sprinter Research Center I am always eager to investigate Sprinter related technical issues.

Group members have noticed that Mercedes Benz has a published torque spec for the injector hold down bolts that seemingly differs significantly from the long standing DC published specs as shown in DC workshop manuals as well as on the instruction sheets that DC at one time included with replacement injectors.

The extended threaded shank length, 85.83mm long, 6.0mm dia., 8.8 grade, factory hold down bolt, hold down pawl and injector seal ring are identical part numbers for both the 5 cyl. and 6 cyl. engines.

Using my 'test' 647 Sprinter cylinder head, which is permanently mounted to one of my work benches, I have recently performed tests related to hold down bolt torque.

This dedicated 'test' cyl head has been quite useful in my repair tooling fabrication.

As many of you know I have developed in-house tools and fixtures for removal of broken hold down bolts, repair to stronger than new stripped hold down threads, and various custom black death repair tools for my in-house use.

This test head features my custom carbon steel hold down threads making it ideal for these hold down bolt torque experiments because data is not compromised by any aluminum thread deformation or failure.

After careful measuring of bolt length (before and after torquing) and injector seat seal thickness to 0.01mm tolerance, and using a calibrated Snap-on electronic 1/4 inch drive torque wrench set to display in/lbs and accurate to 0.1 in/lbs, I have the following observations to report:

TRIAL 1- A fresh, factory hold down bolt torqued to 62 in/lbs (approx 7 Nm) and then an additional 90 degrees, results in 0.08mm crush of a fresh factory seal ring.

The Sprinter's copper seat seal ring features a double convex cross section and the clamping force induced 'crush' creates narrow sealing flats on each side of the ring.

Monitoring the bolt torque during the 90 degree rotation reveals a peak of 180-190 in/lbs before full 90 degrees is achieved and remains at this level all the way to 90 degrees. This peak/plateau signals bolt yield has occurred.

TRIAL 2- A new seal ring and a fresh, factory hold down bolt torqued to 62 in/lbs. (approx. 7Nm) and then an additional 90 degrees X2 (FULL 180 degrees), results in the same 0.08mm crush of the seal ring as well as a steady 180-190 in/lbs torque reading during angle tightening.

Being a stretch to yield, non-reuse, bolt it was not surprising to see permanent elongation. Elongation was approx. 0.30mm for each increment of 90 degrees of tightening rotation (after the 62 in/lb initial torque).

TRIAL 3-A fresh hold down bolt tightened to failure. The bolt tolerated several additional 90 degree sequences PAST the initial 62 in/lbs and 2x90 degrees.

It has previously been reported that fresh hold down bolts have failed when several group members had torqued to 62 in/lbs and then 180 degrees (mistaking 1/2 turn for 90 degrees).

I now suspect this occurred because of bolt bottoming in the base of the blind bore. Bottoming can occur because of debris at bottom of the blind hole.


Tightening the fresh hold down bolt and seal ring will produce the same  clamping force (defined by seal ring crush thickness) regardless of which of the 2 torque specs are used.

The desired residual bolt stress (to achieve essentially infinite cyclical fatigue life) is achieved by both specs but the 2X 90 spec does allow for less care and precision during the tightening procedure.

Torque spec #1 (62in/lbs +90) is certainly less risky if contamination may be lurking at the bottom of the very deep blind bolt hole. I suspect it is also somewhat less risky if the aluminum threads are not in 'as new' condition.

Be sure you test your cyl head's bolt hole threads by using a wire brushed  used hold down bolt with an indexing paint mark, turning in by hand while counting turns, to assure threads are clean and bore is unobstructed to full depth.

This is especially critical when performing black death surgery.

Doktor A   
And for those who wonder about a scheduled injector seal service interval, I uncovered this during my searching.

For my Million Mile Club fleet clients, I have performed scheduled injector removal and copper seat seal replacement at regular 180k intervals.

Keep in mind that these are deep pocketed businesses that cannot tolerate unscheduled downtime and accumulate lots of miles very quickly. I do not necessarily recommend this for the average Sprinter owner.

Doktor A
:2cents: vic
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Well-known member
But then the + 90° turn puts the bolt into yield.

PS Some manuals say + 90° then + 90° again (ie + 180°). I'm not sure which is correct.

Forget this stupid BS imperial torque ratings ,it only leads to silly mistakes and broken bolts or torn out threads as a result.

Use a verified/calibrated 1/4" drive torque wrench set at SEVEN NEWTON METERS .
Plus one pass of angle tightening of 90 degrees.
Let the bolt normalize for a few minutes and do another 90 degree pass.

Needless to mention it, but only use new bolts every time. Don't re-use a bolt in any circumstance.

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