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1989 260e
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Discussion Starter #1
Hello fellow MB enthusiasts. What parts actually wear on the timing chain tensioner? Is it the spring? Or the plunger? I have a new tensioner and was just curious if I should install it. My car is an 89 260e.
 

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W124
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Are you talking about the plastic guide the chain slides against or the spring loaded - hydraulic cylinder assembly that tensions it against the chain? Or both??
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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I would assume that you also have all the guides for the chain as well. There is allot to disassemble to change the tensioner, so it only makes sense to me to change the guides as well. They are more prone to fail than the tensioner.

Good Luck,

Jayare
 

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W124
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If the guide wears its physical and you can see whether or not its worn down or broken. The cylinder as mentioned above does not really wear. What is leading you to focus on the tensioner assembly as a problem?
 

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1989 260e
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Discussion Starter #6 (Edited)
I had misread some info that I thought said that the tensioner was prone to failure. So while I was ordering new rotors I also ordered a new timing chain tensioner. Removed the tensioner from my parts car (88 300e) and didnt see what would wear except the spring or the end of cylinder that i assume pushes on the guide rail by timing chain. Jayare I was only removing the tensioner , and not getting into the guides or the timing chain. No problems with timing chain, noises etc. Just love tinkering and learning about my benz.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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Anyone going to the trouble of doing a head job, should replace the single row m103 timing chain if it has over 100,000 miles. The only caveat is to rent the proper tool (from like peachparts) for joining the new chain. About any chain break can remove the old chain, but only a MB designed tool can reconnect it. It's a weird linked chain....can't say I've seen anything quite like it. If you've joined a lot of chain on different kinds of equipment, you can get by peening it...but I would advise against it unless you know what you're doing. Chain failure can be catastrophic.

The double row chain on the m104, seem to be the Rock of Gibraltar by comnparison.:thumbsup:

Kevin
 

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W124
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FYI, there is a clip inside the tensioner that allows the inner part to locate in grooves in the bore. This is a mechanical adjustment to take up large amounts of slack in the chain. The hydraulic part of the tensioner only compensates for a handful of millimeters of slack. If I recall correctly from the last time I had a head off the 103s you have to push the inner part of the tensioner out and separate it from the outer (bore). You reinsert the inner portion and put it back in the block but don't install the plug until you are ready to tension the chain. Once under spring pressure the inner portion will self-locate against the chain. At that point you just reassemble the assembly. No adjustment necessary.

By the way, my 88 has 289,000 miles on the original chain.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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"By the way, my 88 has 289,000 miles on the original chain."

Why would you brag about something like that? I think the OEM chain cost me $50....why would you endorse using a single row chain for such a long mileage period-given that chain failure under load like high speed or accelerating can cause catastrophic damage to your engine? :eek:

Kevin
 

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"By the way, my 88 has 289,000 miles on the original chain."

Why would you brag about something like that? I think the OEM chain cost me $50....why would you endorse using a single row chain for such a long mileage period-given that chain failure under load like high speed or accelerating can cause catastrophic damage to your engine? :eek:
I once had similar mileage on a 103 motor chain and a couple of really good factory trained mechanics advised against changing it. Virtually all 103 and 104 motor timing chain problems come on "molested" chains. You only get one opportunity to have a factory linked timing chain.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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I once had similar mileage on a 103 motor chain and a couple of really good factory trained mechanics advised against changing it. Virtually all 103 and 104 motor timing chain problems come on "molested" chains. You only get one opportunity to have a factory linked timing chain.
Well, that is utter bullshit.....especially since MB makes a tool (or has it sourced to their specs) that accomplishes exactly that; a finished, factory link. ALL chain stretches to a point where it becomes suspect for continuous reliability. Whadda think, MB has some factory, zillion $ voodoo machine blessed by the MB God that puts the chain together, one time and one time only? Just more faux mystery and hype around the marque. And another ridiculous stab at me, deanyel.

Kevin
 

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No one is taking a stab at you. They just aren't problematic. To change a properly working and sounding factory 103 timing chain is to introduce risk, not mitigate it. You're at odds with the factory on this - there is no recommended preventative maintenance replacement interval for a properly working 103 timing chain.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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Yeah there is a change interval-high mileage for preventative catastrophic insurance and good mechanical sense. The factory can't give a change interval due to the fact that drivers change their oil with random frequency, use different oils and exhibit different driving styles.

And...you've completely ignored the fact regarding the MB tool specifically for linking the chain back together, perfectly. You're insinuating there are 'stories' abound of owners replacing chains and having catastrophic failure from their replacement techniques-show me the evidence of the failures when using the factory tool? You are therefore scared of something you don't know-call it mechanical ignorance if you will. Your lack of knowledge on chains would indicate that this is one repair, you probably shouldn't do. And in your original reply, you talk about the m103 and m104 chains together as if they are the same chain-one is a single row and one is a double row...quite different animals.

Kevin
 

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About a dozen 1988, 1989, 1990, and 1991 sedans, wagons, 4Matics and 1 coupe
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Does MBZ sell a full loop chain for the M103 for someone wishing to go through the hassle of removing the whole front cover? Or is one with the "last" link unfinished the only option?
An acquiantance of mine had an old BMW Bavaria and he was obsessed with replacing the timing chain. BMW sold only a completed chain (at least at the time they did) and my coworker didn't want to pull the front of the engine apart. Luckily we were doing work for BMW at the time and traveling to Munich. He found an engineer there who was able to provide an unfinished chain for him to take home and loop through the engine and swage the last link.
My TE#2 is approaching the 225k miles mark and I admit that I think about that chain whizzing around in there as I'm blasting along at 85 mph.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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I don't know if they do...BUT that would certainly alleviate anybody's reservation in doing this task. And if you go that far in, you might as well replace the short oil pump chain as well. However, if you closely examine the timing chain and then the MB tool that joins the links (especially with your mechanical background augapfel), I really think you'd find it a fine repair to just use the tool.

Yeah and anyone with that kind of mileage, should by worrying about that chain whipping around at 80+ mph. ;-) Just because it's not an often sited catastrophe, doesn't mean it can't happen to you...especially buying used cars that 'others' have owned and maintained.:thumbsup:

Kevin
 

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"By the way, my 88 has 289,000 miles on the original chain."

Why would you brag about something like that? I think the OEM chain cost me $50....why would you endorse using a single row chain for such a long mileage period-given that chain failure under load like high speed or accelerating can cause catastrophic damage to your engine? :eek:

Kevin
I haven't seen enough information to justify replacing the chain just because the head is off. IMO the difference between the original new chain and one that has a couple of hundred thousand miles on it is that one of them is longer. You may feel differently and I suspect that is why you went through the expense and trouble of changing it. The difference between your view and mine is that I am not confident a chain joined in my garage with a second rate tool is as reliable as a chain joined at the factory under much better conditions and with much better equipment. Chances are good that my car will not see a chain break before something more financially catastrophic turns it into a parts car.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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I haven't seen enough information to justify replacing the chain just because the head is off. IMO the difference between the original new chain and one that has a couple of hundred thousand miles on it is that one of them is longer. You may feel differently and I suspect that is why you went through the expense and trouble of changing it. The difference between your view and mine is that I am not confident a chain joined in my garage with a second rate tool is as reliable as a chain joined at the factory under much better conditions and with much better equipment. Chances are good that my car will not see a chain break before something more financially catastrophic turns it into a parts car.
Fair enough...I just don't agree on something so critical and relatively easy/inexpensive to replace. The tool isn't "second rate" and expensive to buy-that's why you rent it. As I said, it's just a chain, not voodoo MB mystery science. A properly joined chain should look/act exactly like a factory chain. Agreed though....if you don't feel comfortable doing something, you probably shouldn't do it. The chances of your old chain breaking, against someone who replaced it using the correct tool are exponentially higher-however rare. I'll take my chances with a new chain.:thumbsup:

Kevin
 
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