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Old 07-26-2001, 08:34 AM
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I went by the shop yesterday and saw a nice looking little 190 with the engine disassembled. It seems the chain (single row) broke and let the valves hit the pistons. Major rework in order. Guys/Gals get those timing chains replaced if you haven't done it in a while! It is easy for a shop to roll in a new chain. Do it or be sorry later.

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Old 07-26-2001, 11:16 AM
G-Benz's Avatar
Razorback Soccer Dad
Join Date: Apr 2001
Location: Dallas/Fort-Worth
Posts: 5,711
Mine on the W124 should be a double row...I believe they are not as much of a problem as the single-row type. Does anyone know how many miles on average you can get out of these things?
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car
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Old 07-26-2001, 11:47 AM
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Benz Zealot
Join Date: Jun 2001
Location: Houston, Texas
Posts: 838
I just did a quick search on the MB archives over at the MB mailing list and found this:


My observations on the 103 engine timing chain are based on what I asked my shop, the Mercedes Service Center.....The owner said "Not to worry about it". I would consider them to be experts.

And despite your assertions that the 103 engine "won't make 300K miles" there are already a number of them with 200-250K miles without major work done.

I think the following observations are in order in re: timing chain life

1. Different engines have different designs & length of travel.

2. A few engines had a single row design making timing chain life a major consideration.

3. If changing were that critical, this would be in a DBAG recommended maintenance procedure.

4. If doing something such as a valve job, it would be foolish NOT to change the chain, since you're 3/4's there.

I agree with your remark about the experts...However if we all relied only on "experts" input this would be a rather quiet list. I would number the people I've known on this list as "experts" over the years as < 10...I of course do not consider myself among that group.

Should you change a chain based on mileage? On some models the question is more relevant than others. If my 300E had 175K miles I would consider it. One certainly can't harm a vehicle by over-zealous maintenance...

Certainly your remarks about relative cost of a chain vs an engine overhaul are correct - who would disagree with that?

I stand by my assertion...


Basically, I wouldn't worry about it unless you're having work done in that area.


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Old 07-26-2001, 02:34 PM
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If you will refer to your Star magazine about 3 mos. ago, a dealer reflected on the problems encountered with the w107 sl's. His dealership used to recommend replacing the single row on 380's every 50K. They later experienced failure on a customer's vehicle at 30K. Subsequently, they recommended going to the double row for all. I do not intend to argue the point. It is obvious what recommendations one will find from those that have any knowledge of the subject. By the way, the poor lady's 190 four banger will have to remain a single chain since the timing cover contains the oil pump mechanism.
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Old 07-26-2001, 03:03 PM
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Okay, so a 190 broke a chain. The important thing is, which engine did it have?
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Old 07-26-2001, 04:13 PM
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Join Date: Feb 2000
Posts: 171


My 190E 2.3 has 260k miles on it. How often should the timing chain be replaced? As far as I know, it's been changed once..........Any ideas?


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Old 07-26-2001, 04:17 PM
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My 190 2.6 (1992) had the Duplex-rock solid Its still going strong approaching 200K. Timing chains on the earlier models were known to be suspect,after significant mileages-
similar to cambelts on other manufacturers cars, which of course are renewed at the appropiate mileage by careful owners.

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Old 07-26-2001, 10:21 PM
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Larry, do you hang out at the local Mercedes shop often? My Father's 420 threw the timing chain a few years ago. And when the S430 approaches 50K, we will change that one, too.
Last year I went by the local shop here in town and there was a 420 with heads off because chain was thrown. Last week as I went by I noticed the 190 four banger in the shop had a chain thrown causing extensive damage. Well, I wonder if changing an older chain in M/B's would be a good idea? Duh!! Go to a mercedes salvage yard and ask the guys about timing chains. The problem is easy to understand if you consider it takes a 5 or 6 foot chains to go around the bottom end up to one head back down into the timing cover and over to the other head.

For that matter, the short timing chain in chevy V8's may need replacing in as little as 50K. That is why my LT4 vette has a severe duty roller chain.
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Old 07-27-2001, 12:34 AM
R Easley
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Another broken timing chain!

The two MB engines with the most "timing chain problems" are the 3.8 in the early 80s 107s and 126s and the 4.2 in the 420SEL (i.e., 126 chassis) from 1986-on.

The early 3.8s had a single row chain in the *US* only, I believe and, by 1984 (I think this was the year), the factory went back to the double chain for US models because of breakage of the single row chains. Important note: if you are considering a 107 (SL) purchase (now or in the future), please check to make sure that the potential buy has a double chain. If it doesn't the cost to replace is a cool $3000 or so on this model, so make sure that this is factored in to the purchase price. If I owned a single row chain 3.8-equipped MB, I would *park* it until it was converted to a double-row chain.

In contrast, the SELs are, relatively speaking, much easier to replace. Also note that, even though the 103 engine (pre-93? 300Es, and 88-89 300SELS) has a single chain, it is *not* a problem. Again, the 103 engine's single chain is not a problem. It is an inline six and has a shorter chain.

On the 420s, the "timing chain problem" is actually a timing "rail" problem -- specifically, on the driver's side. If you find a 420SEL with jumped time, 99.999% of the time, it will be the driver's side. The problem is a timing chain rail that gets brittle over time, breaks, interferes with the chain b/t it and the cam gear, and the chain jumps time and bends valves. I have a friend on the left coast who has been in the business for years as a service manager and a technician and his "fix" is to cut (yes, cut) the offending rail's end that breaks when he puts in a new rail.

I have not owned a 420SEL, but probably will buy one when the right deal comes along (read: jumped time, owner doesn't want to reapir, will sell cheap). Almost bought one this past winter, but the owner decided to rebuild the engine.

If you are a reader of this site, and are looking for a luxurious, yet *reasonably* inexpensive MB *and* you are an accomplished DIYer, I would highly recommend the 420SEL as a potential bargain -- there are plenty of them out there -- now and there will be in the future - with jumped time.

Personally, if I owned (or bought) a 420SEL, the *first* thing that I would do -- regardless of the miles on the car or engine -- is replace the offending timing chain rail with a fresh one that has a fresh "cut" in it . . .

Richard Easley
Waco, Texas
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Old 07-27-2001, 07:37 AM
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Southern Son,


In case you didn't notice when you were spending all this massive amount of time hanging around the MB shop, the 430 you spoke of is a V8. On the V8 you have two banks of cylinders, and many have four cams. This indeed requires a very lengthy chain with numerous sprockets, guides, etc. Most inline engines have a relatively short chain and quite a few less components.

MOST of the inline engines are much simpler in chain layout. Since the M103 engine, most of them have a ratcheting tensioner. A chain failure in the M103 is quite rare.

I am not an advocate of ignoring timing chains. I have replaced a few, which, when upon checking, showed to be "stretched". Notice I said, upon checking. It's not like there is no way to tell if a chain has worn. Are you aware that the chain stretch can be measured? A belt is a different thing, you can't really inspect it to see if it should be changed, thus there are recommended intervals for belt change, and rightfully so.

I also know from personal experience that chains in engine models with a decent chain life history, frequent oil changes will prevent timing chain "stretch".

I'm sure the salvage yards are full of engines with broken timing chains. The salvage yards are where the cars that never get the oil changed end up prematurely. Duh!! I wonder if I should change oil often?

Change oil hot and change oil often,
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Old 07-27-2001, 08:36 AM
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Larry, you are absolutely right! If I were you, I don't think I would even consider chain stretch. You ought to just keep on truckin' and not worry one iota about it.
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Old 07-27-2001, 08:49 AM
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R Easley, YOu are correct about the 380 chain conversion hassle. I just did mine here at the house the last few months. For some reason M/B decided to tuck the intermediary gear drive for distibutor up under the left head. Anyway, I was able to determine I had an oil leak in rear flange, I was able to do a complete valve job and replace a few parts while I was at it on the injection system. Car does much better now and my air is quite cold with the 134a conversion, also.

For the cheap insurance of rolling a new chain in an overhead cam motor, I really don't understand the reluctance of some to do this. The M/B silicon/aluminum block is practically wear proof and requires only attention to those weaker items for that incredibly long lived engine life.

As far as the V8's go, they are more susceptible to the broken/jumped chain, however the poor little lady's car that I saw last week was of the small 4 cylinder variety. I do not know if the rail failed on that 190 or if the chain just gave out. In any case, she went too long before replacing it.

I suppose you could say that since I have background in owning/maintaining some expensive equipment (cessna, chris-craft cruiser, vettes and M/B), I don't have to be knocked down by overwhelming evidence before I choose to take pre-emptive measures.
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Old 07-27-2001, 11:31 AM
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I realize that I am not very articulate, but I guess I am really not doing well on this, or maybe everyone is not reading everything that I'm keying in.

I must not have made it clear that I do worry about my timing chains and check for stretch reasonably often. I guess that didn't come across very clearly, because surely no one would respond without reading ALL of a post first. When I see a stretched chain, or other indications of the need for a new chain, I roll one in as well as replacing whatever components seem flaky.

My point is that I don't just roll one in because the car has traversed a certain number of miles, or the phases of the moon indicate it.

Taking this approach, I have yet to lose a chain OR an engine.

If these were belts, I would be replacing them more frequently than the manufacturer indicates because I have no way of inspecting them.

If you would rather roll in a new chain than inspect and measure, I say that you should go for it. BTW, do you know how to check a timing chain for stretch?

Have a great day,
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Old 07-27-2001, 11:54 AM
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yes...and I am sure that if you stop by your local M/B independent shop, they will be glad to show you how, also.

[Edited by Southern_Son on 07-27-2001 at 12:08 PM]
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Old 07-27-2001, 05:49 PM
Registered User
Join Date: Apr 2001
Location: Washington, DC
Posts: 223
Originally posted by Southern_Son
Larry, do you hang out at the local Mercedes shop often?
Originally posted by Southern_Son
yes...and I am sure that if you stop by your local M/B independent shop, they will be glad to show you how, also.
Gee, this seems a bit harsh -- Larry has made many knowledgeable and helpful posts on this Board and IHMO these sorts of extraneous comments don't really advance the discussion.

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