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2007 W211 E320 Bluetec
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Discussion Starter #1 (Edited)
Can you please have a look at the attached image and tell me if my tensioner is in good shape and consequently timing chain isn't stretched too much? Can some one explain how do you visually inspect the tensioner?
Thanks

Update: searched the web and found a thread about it on mbworld. This one is extended indicating stretched timing chain:
https://mbworld.org/forums/attachments/diesel-forum/410988d1502577367-om642-chain-stretched-photo-chain-tensioner-om642-chain-tensioner.jpg


It would appear that I'm ok.
 

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E320/E250 Bluetec Ford F350 6.7l
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What is your mileage?
Any bad symptoms? Why you worry?
I never had to do it, but remember from W124 the chain stretch measurement by comparing degrees on main pulley.
They should have something similar for newer engines.
 

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2007 W211 E320 Bluetec
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Discussion Starter #3
It would appear that it's a common thing for OM642 diesel engines in 2010 and up vehicles for the chain to last less than 100k miles. I have see reports of replacent needed at 70K miles. Nuts!
I'm at 170K km so wanted to make sure I'm OK. I have no chain noise but I'm seriously considering changing my engine oil at half the recommended interval.
 

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E320/E250 Bluetec Ford F350 6.7l
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My 642 sucked water at over 180k and I did not hear any chain problems.
Not too many of those engines went over 200k, so experience is limited, but beside few European models, timing chains on MB are million miles item.
So where did you hear about those problems?
 

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E320/E250 Bluetec Ford F350 6.7l
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This guy decided to replace his chain at 54k miles without investigating if the old one is really stretched.
Not really good statistics as this is newer, slightly different engine mounted in GL.
I read the long thread by other guy who had his DEALER MAINTAINED engine seized at 80k due to sludge.
There is some myth if dealers dump their surplus oils in those engine, but seems the newer generation is very oil-sensitive.
I just order MB oil for both of my BT (have rebuild 642 that I bought in England) and will send samples to Blackstone.
 

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W219 320CDI -07 W220 320CDI -01 W210 270CDI -01 EX: W211 320CDI -04
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See this thread:
OM642 jakoketjun venymä :: mese.fi

First pic 274000km, stretched (later mechaninc says timing was off 15 degrees)

Second pic is newish 20000km driven, and third pic first one after chain changed.

On page 3 nice pics about how much longer chain is...
 

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2007 W211 E320 Bluetec
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Discussion Starter #8
On second look it'll have to be done soon. More tools needed...
 

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W211 E320 CDI V6 FL Avangarde Sports Package Wagon
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Hey EFSiR, Did you do something with this tensioner? Do you hear any noise during startup or when engine is running?
 

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2007 W211 E320 Bluetec
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Discussion Starter #10
This is original tensioner and by the looks of the extension original chain too. No, I don't hear anything yet. At least nothing major. I'll probably take on this repair in the spring along with all 6 injector seal change utilizing Honda copper crush washers (Honda part# 16472-RBD-E00).
Pozdrawiam!
Czarek
 

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W211 E320 CDI V6 FL Avangarde Sports Package Wagon
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OK, I wonder if only changing the tensioner could make a difference. 170k km is a not a big mileage, maybe it was serviced poorly before.
I'm also curious if this lookup method is trustworthy, I guess unless you don't hear any rattle, there's nothing much to do, well maybe some preventic maintenance like changing only this tensioner now.
Anyway, please let us know about any changes.

Pozdrawiam,

Grzegorz
 

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E320/E250 Bluetec Ford F350 6.7l
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Still remember "troubleshooting" the chain on Fiat125.
If you can see it - time to replace.
You had to hurry or the engine would run out of oil with all the splashing from hole in the cover.
I am getting ready for 642 engine swap and the rebuild engine I've got from UK has original chain with unknown mileage.
I will dig up the method from 603 engine and see if I can compare the chains.
Krzysztof
 

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2007 W211 E320 Bluetec
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Discussion Starter #13
Will there be a difference in the tensioner state when inspecting it with a running engine? My picture is of a tensioner with engine off.
 

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W211 E320 CDI V6 FL Avangarde Sports Package Wagon
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I don't know, you could try, but wear some eye protection, hot oil will be splashing...
 

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W211 E320 CDI V6 FL Avangarde Sports Package Wagon
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This guy had a rattle on startup, replaced the tensioner, works good.
 

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2005 E320 CDI, 1992 300TE, 1999 Porsche 911 Cabriolet
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Why are you replacing a timing chain? They can last almost forever. What are you seeing or experiencing that motivates all of this work?

Regards,
Peter
 

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E320/E250 Bluetec Ford F350 6.7l
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I am in process of swapping my short block and disposing the one with 183k miles.
Took camshafts already out and they dont' show any wear, or ovals between the sprocket teeth.
Waiting for new E16 socket with 1/2" drive to arrive as I already broke 2 wrenches trying to take the heads off.
Old test was pull the chain out and see how much it sags, when hold horizontally.
Anybody wants me to do other test or take a pictures?
Now it is good time.
 

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W211 E320 CDI V6 FL Avangarde Sports Package Wagon
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Why are you replacing a timing chain? They can last almost forever. What are you seeing or experiencing that motivates all of this work?

Regards,
Peter
Unfortunately that is not true when you have OM642. Nothing can last forever.
Tensioners in V6 fails very quickly 200-250k km. When there's a 1-2 sec sound of chain, without a cover and with opened hood, tensioner can be changed and there's a good chance that it will running smooth again.
If neglect it, chain will be stretched eventually. It's hard to notice first, with closed doors and hood.

https://www.motor-talk.de/forum/320-cdi-v6-steuerkette-t5628569.html?page=1

Regards
 

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2005 E320 CDI *black on black with nearly every option*
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I had a failed tensioner on my om648 at 420k miles. had the classic "loose timing chain" rattle on startup. The tensioner had siezed! Just for preventative maintenance i decided to change my timing chain and check wear on the guide rails as well. Original chain with 420,000 miles on it had about 2mm of stretch compared to brand new chain!!!! That's incredible that the chain could last that long, and probably last another 500,000 miles without significant stretch. The rails had less than 1mm worn off the wear surface, those could also last 2 million+ more miles. The engine was CLEAN, no sludge no varnish, no discoloration anywhere at all. Absolutely incredible when you think about it. What a marvel synthetic oil is.
 

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2006 cdi, 1993 500e
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It's really gets into how long the chain is. On a V8, they are very long.. 0.002-3 thousands per link of wear adds up when it's 15 feet of 3/8 chain. The idea is to replace the chain before there is significant wear to the chain and sprockets. At some point, you probably wear through the hardened layer and wear goes up really fast. Sprockets would be a pain and expense to replace.

OM642 has some modern "low friction" chain to improve fuel economy. Doubt you can relate it to a OM648 or any previous diesel.
 
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