Timing Chain - How Long Can I Hold Off?

Pneumo

Member
Hey all,

I've searched around and believe my timing chain and tensioner need replacement on my 156k mile 08. On a cold start I can hear an audible rattle from the timing chain for 2-3 seconds which then resolves (I assume this is the time it takes for the tensioner to build oil pressure and engage the chain guide), this happens 2 out of 3 times I start the engine from cold. Once the oil comes up to temp, any subsequent start that day there is no noise whatsoever and I am unable to perceive any other rattle from the timing chain while running or idling. I have been experiencing this issue for ~10k miles, and only now determined what the issue was.

My question is, how long can I keep driving the vehicle before replacing the timing chain and tensioner? I am currently 2-3k miles from home. Waiting that long makes me a bit nervous, seeing as chain failure while driving home would likely result in needing a new engine. But maybe someone with more experience might be able to give me a better idea of how risky this would be.

I have purchased all the parts, manuals, and tools needed and plan to do the work myself. I also have all my other tools with me. If necessary, I can likely find a rent-a-bay and try to tackle it sooner, but I'd prefer to be home where I'd have more resources and don't have to pay for a bay somewhere.

I plan to do an oil change before heading home, knowing I'll have to do another when I complete the job. Is this likely to help the tensioner to gain oil pressure sooner, or is this noise definitely a "stretched" chain which the oil change wont help?

I appreciate any info or advice. I'm trying to make the best of a bad situation!

Thanks in advance!
Ian
 

Pneumo

Member
Thanks for the bump Bob!

Thanks also to you showkey. I've been reading pretty extensively on other forums regarding the issue and repair, you're right, there is an awesome DIY guide and tons of info elsewhere.

I'm not looking for a definitive countdown just trying to understand if I'm on the verge of complete chain failure, or if it's likely to progress in a manner that I can moniter in any way. Or if it's a "do it now dummy!" sort of repair. If anyone has experienced the same issue and how, if, it progressed before you repaired it or it nuked the powerplant.
 

Bob Laps

Active member
IMO if u can hear something it's time to do it....it would suck if u had the opportunity to fix it and something went wrong

Bob
 

Pneumo

Member
Yeah, I guess that is the conclusion my mind came too as well. Which is why I ordered all the parts and specialty tools.

I suppose I'm now on the hunt for somewhere to hunker down and do the work. Hopefully I can find someone locally with a pole barn who amenable to letting a couple of kids park their rig inside for a week.... Hah! Anybody know someone like that in the St. George, Utah area? Lol.

Maybe I can sneak into some jeep forums and plead my case, those guys always seem to be big into DIY work and Utah is bound to have someone willing to help out!

Thanks all, I appreciate your help so far. Still happy to hear any other advice or opinions.

Our website is www.thevanimals.com and our instagram is @the.vanimals if anyone wants to take a look at our rig and travels.
 

Midwestdrifter

Engineer In Residence
What oil are you running? A 40W might reduce the noise. Running a oil system cleaner through for a few hundred miles before an oil change can sometimes improve tensioner pickup.

Check the pan for pieces of the tensioner guide. After draining the oil, put a endoscope or boroscope into the oil drain hole.
 
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Pneumo

Member
What oil are you running? A 40W might reduce the noise. Running a oil system cleaner through for a few hundred miles before an oil change can sometimes improve tensioner pickup.

Check the pan for pieces of the tensioner. After draining the oil, put a endoscope or boroscope into the oil drain hole.
I've been running 5W-40 for all of my oil changes. Are oil system cleaners recommended for DPF and EGR equipped vehicles? For as sensitive as these systems are to the wrong oil, I'd be hesitant to run anything without some more info.

As for checking the oil pan, I may pull it and look when I do the repair. It's not clear to me how it would break into pieces however, is this common? It interfaces with the plastic guide and is pressurized with oil, so it breaking apart doesn't make sense to me logically. Unless it's some kind of internal mechanical failure, I wish I could find a cutaway of the OM642 tensioner to understand it better but ah well!

Thanks for the advice either way! I'll read more into tensioner failure on these.
 

Midwestdrifter

Engineer In Residence
By tensioner pieces, I meant the guide itself. Not common, but I have seen it happen on various engines over the years. The plastic cracks due to a sticky tensioner, and gets hammered by the chain.

In the far north, vehicles with too thick of oil for the temps will take a bit of time for the tensioner to fill, and the cold makes the plastic in the tensioners guide brittle enough to break.

For a short run, a cleaner won't cause any harm. They don't usually contain phosphates, so DPF contamination is highly unlikely. If concerned look for one with DPF safe on the label.
 

Pneumo

Member
By tensioner pieces, I meant the guide itself. Not common, but I have seen it happen on various engines over the years. The plastic cracks due to a sticky tensioner, and gets hammered by the chain.

In the far north, vehicles with too thick of oil for the temps will take a bit of time for the tensioner to fill, and the cold makes the plastic in the tensioners guide brittle enough to break.

For a short run, a cleaner won't cause any harm. They don't usually contain phosphates, so DPF contamination is highly unlikely. If concerned look for one with DPF safe on the label.
Ahhhhhh, that makes a ton more sense. This van lived in Minneapolis for 10 years before I bought it, and spent last winter in Northern Wisconsin. Started like a top up there, didn't start hearing issues until we were a few months into warmer weather.

I'll take a look and try out one of those cleaners, thanks for the info Bob!
 

manwithgun

Unknown member
Be cautious of the “slide-hammer” injector removal technique that was shown in the mbworld tutorial if you plan to reuse them. These Sprinters use piezo crystal injectors and subjecting them to excessive shock could “possibly” damage them. Hopefully they’ll just wiggle out with a little soaking and a tug, but there are other methods and tools that are more subtle than the hammer.
 

Pneumo

Member
Be cautious of the “slide-hammer” injector removal technique that was shown in the mbworld tutorial if you plan to reuse them. These Sprinters use piezo crystal injectors and subjecting them to excessive shock could “possibly” damage them. Hopefully they’ll just wiggle out with a little soaking and a tug, but there are other methods and tools that are more subtle than the hammer.
Thanks for the warning. I've read pretty extensively about injector removal on here, I've had to rectify a leaking injector seal once already.

I have the opportunity to start prepping those now, what would be a good solvent to shoot a small amount of around the injectors? A few heat cycles along with that solvent should hopefully help free them up, if not I'll give something else a shot.

Speaking of injectors, is there a specific antisieze I should consider using on them when reinstalling? I'd imagine just about any high temp antisieze would work but I'm open to more specific suggestions.
 

Midwestdrifter

Engineer In Residence
I like a zinc rich primer for the injector bodies. That actually prevents the corrosion that often causes stuck injectors. If you search for aircraft type zinc-chromate primer you will find some good products.
 

Pneumo

Member
I like a zinc rich primer for the injector bodies. That actually prevents the corrosion that often causes stuck injectors. If you search for aircraft type zinc-chromate primer you will find some good products.
I'll take a look around and pick some up. Thanks again!!!



Side note. I was in the Merc dealer here for a part today and asked if I could get a quote for the timing chain job. The service rep I was talking to said in 15 years, he had never seen a failed chain which I thought was somewhat comical. Stretched chains seems common on all OM642 derived platforms. I took his response as an attempt to get me into the shop for diagnostics, and or a lack of interest in helping a 25 year old asking for something out of the norm....

Ah well....

I was also able to find someone locally who is willing to let me park on their property and offered to help out with the job as needed. Props to the Jeep community for that.
 

Thump_rrr

Active member
I'll take a look around and pick some up. Thanks again!!!



Side note. I was in the Merc dealer here for a part today and asked if I could get a quote for the timing chain job. The service rep I was talking to said in 15 years, he had never seen a failed chain which I thought was somewhat comical. Stretched chains seems common on all OM642 derived platforms. I took his response as an attempt to get me into the shop for diagnostics, and or a lack of interest in helping a 25 year old asking for something out of the norm....

Ah well....

I was also able to find someone locally who is willing to let me park on their property and offered to help out with the job as needed. Props to the Jeep community for that.
Whether the service advisor has seen one or not he must have the book hours required to do the job somewhere.
 

Pneumo

Member
Whether the service advisor has seen one or not he must have the book hours required to do the job somewhere.
Right? He seemed pretty disinterested in helping me, so chalk it up to poor service I suppose.

I was really just hoping to see what I'd be in the hole for if I have to admit defeat and have it towed to them. Pretty sure I'll be looking elsewhere if it comes to that. lol
 

lindenengineering

Well-known member
No its not poor service its covering your butt!

The basic job is basically 12 hours--BUT --what if the chain tensioners and slipper blade guide rails are worn. They are only available in a complete kit (basically the whole lot) and should you have to install them its an engine out job, plus a partial tear down & that equals 32 hours on average of labor time plus parts/materials .

So to avoid the customer objection of WELL YOU SAID!!!! & infantile like melt downs in reception Service Writers are reluctant to quote such a job! Unless it is physically seen and & partially inspected by their their tech staff & then they can quote from a position of familiarity with the job.

I have done this actual job several times and one thing you absolutely DO need to feed the new chain in against the old trailing one is a split link with retention clip otherwise you run the very real risk of losing the chain in the timing case ; Then its a rip out and "engine on the floor job" or on a stand.
To hold the chain on a dummy sprocket is advisable prior to riveting the joining like is essential. I use a pair of modified long nosed grips to hold each end onto the sprocket as a anvil & guide arrangement . Not an easy job!
In fact I have just done one on a 0M616 engine in a D 370 framed van .
In short a PITA
The chain itself was OK (just) however in the process I found an idler sprocket wheel tooth hooked and the half time cam sprocket had previously been installed backwards so it has wore the sprocket flanks. This in effect required whole new drive sprocket set up. Beaucoup Bucks and weeks of waiting for parts from Germany.
Blew the repair budget out the window!
Dennis
 

Pneumo

Member
No its not poor service its covering your butt!

The basic job is basically 12 hours--BUT --what if the chain tensioners and slipper blade guide rails are worn. They are only available in a complete kit (basically the whole lot) and should you have to install them its an engine out job, plus a partial tear down & that equals 32 hours on average of labor time plus parts/materials .

So to avoid the customer objection of WELL YOU SAID!!!! & infantile like melt downs in reception Service Writers are reluctant to quote such a job! Unless it is physically seen and & partially inspected by their their tech staff & then they can quote from a position of familiarity with the job.

I have done this actual job several times and one thing you absolutely DO need to feed the new chain in against the old trailing one is a split link with retention clip otherwise you run the very real risk of losing the chain in the timing case ; Then its a rip out and "engine on the floor job" or on a stand.
To hold the chain on a dummy sprocket is advisable prior to riveting the joining like is essential. I use a pair of modified long nosed grips to hold each end onto the sprocket as a anvil & guide arrangement . Not an easy job!
In fact I have just done one on a 0M616 engine in a D 370 framed van .
In short a PITA
The chain itself was OK (just) however in the process I found an idler sprocket wheel tooth hooked and the half time cam sprocket had previously been installed backwards so it has wore the sprocket flanks. This in effect required whole new drive sprocket set up. Beaucoup Bucks and weeks of waiting for parts from Germany.
Blew the repair budget out the window!
Dennis
I was really just hoping for a ballpark idea, but based on what you've said, I can see how that wouldnt have been a simple ask. I retract badmouthing the service tech, just in a down mood having to do this repair at all.

I just got the Mercedes WIS up and running today, I have yet to look at replacement of the guides. Is that really an engine out job? That would no doubt be above my pay grade. My impression was that the timing cover could be removed in chassis and the guides replaced, though like I said, I have not yet gone through the Merc manual to verify.

As for replacing the chain itself, I have all of the specified specific tools from the manual, to include the bicycle chain esque master link for connecting the old and new chains. The job seems relatively straight forward, albeit time consuming. Are there any specific indicators I should look for when determining whether or not to replace the guides?

Anyway, thanks for the info Dennis, very helpful.
 

gonzo42

New member
You can put it off right up until the time it breaks.

Are these engines "Interference" or "Non-interference"? This referring to whether a broken timing chain will cause a collision between the valves and pistons?
 
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