Well, where do the 5-cyl diesel engines stand when it comes to the timing chains? Is it critical for them as well, like the V8 models, or are they more like the I-6 models when it comes to this?

To update on this old thread I started last summer, I ended up buying a 1985 380SE. From what I have learned on the forums here, this is one of the engines where the chain/tensioner/rail replacement is critical. It is my understanding that a 84-85' 3.8L V8 has been upgraded to the double chain, as opposed to the single chain on the early 80s 3.8L.

Unfortunately, the previous owner (which was the 2nd owner) does not know if or when any of this had been replaced. The car had 220K when he bought it in 2000 from the original owner. He drove to car to its current mileage @ 263K. I have started the car when cold and I do not hear any noise and the oil pressure is high. I am assuming that with 263,800 miles, that it has been changed at least once, or else this engine would be history? What is the highest miles on the original chain you have heard of on a W126 V8? I wish there was some way I could find out from the original owner to see if it ever was changed. One would think that if they bought this car new and kept it for 20 years and put 220K that they would have surely changed the chain, or would they? Did they maintain this car well, or did they let everything go? As far as the appearance of the car, as well as the running, it appears to have been well maintained and garage kept, but we may never know for certain.

I have phoned two of the three known local Mercedes independent repair shops to get an estimate on a chain and tensioner. One place quoted me $520.00 and the other said between $600-$700 (which included changing the upper rails). I do not know if the $520 quote included that or not. I did not know anything about those at the time. I am going to call the last place tomorrow to get a quote from them.

It is a perfect running car and aside from two windows, everything is in perfect working order and it is 100% rust free with excellent interior. I only paid $1000. for it, so I think I would still be doing fine if I paid $500 for the replacement.

So, if this was YOUR car, would you change it right away, or would I be taking too much of a risk driving for a few months on the current chain/tensioner/rail? It may indeed still be fine, but then again, it may be in the brink of disaster. I know that if something breaks, it would be a $3000+ repair, which in that case, I would have to salvage the car. It is one of those mysteries. I know everyone is thinking, would you rather pay $500-550 now, or $3000 later?

One of the reasons I hesitate is that the car runs so well. I hate the thoughts of them dismantling the car for this. I know several things have to come off. I keep thinking what if they mess something up? All three are certified professionals for Mercedes repairs, but I am still concerned about what if something gets broken and I have to shell out more $$$. I guess I would have to check with each individual shop to see how they work.

Sorry for the long post, but I wanted post this here.

Thanks for any input.

,,.at least have the chain guides examined - those are the problem, not the chain itself.

As Jonathan posted last summer, it is cheap insurance to replace the upper guides, chain and tensioner. Make sure they do the oil tubes while they are in there.

I must admit though, that the probable $750 or so to have it done seems out of whack with your purchase price. $1000 is almost like buying a "disposable, single use" item At that price, you have to assume you must spend some dinero on presumably deferred maintenance if you don't have the records.

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"Dangerous with a wrench...and not smart enough to know it"

Stable (in order of acqusition):
'84 500SL, 280SEL (Euros)
'77 280SE. '90 560SEL
'79 450SEL 6.9,
'95 C280 (totalled by daughter 8/07)
'81 280SL (rescued) '88 300CE
'86 560SEC '95 C36
'01 CL55

DD's: '04 S500 4Matic (SWMBO)
'04 F150 Crew

One place quoted me $520.00 and the other said between $600-$700 (which included changing the upper rails).
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Those are pretty good price quotes. If you plan to keep the car you should go ahead and do the replacement. The chains hardly ever break. The problem comes with the plastic guides/rails. They become brittle over the years and if you do get any chain slap from a loose chain/tensioner the slap will break the plastic and it falls into the chain, the chain jumps time.....then you have a major engine failure.

__________________
1986 560 SEL (159K miles)

If it were my car I would have the needed parts on order and probably do the job in the next 2-3 weeks. I'd have the best shop do it, not the cheapest.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Thanks guys. I keep hearing "chain guides" and "upper rails". Are these two totally different things? If so, do I need to have the following checked/replaced:
chain, tensioner, rails, and guides?

The $525 quote was only when I asked about replacement for chain and tensioner. I am assuming it would also consider the other things involved with this chain replacement. I am going to phone back tomorrow and find out.

The lower quote was from a very reputable shop from what I am told. I have not heard a lot about the other two mentioned.

There used to be someone here on the forum that lived in the same area as I do and they mentioned these shops before, but I cannot find it on the search. I will try again.

I guess I will definitely at least have it checked out within a couple of weeks. If I do go ahead and drive it, would it be best that I drive at low speeds, or does that not make a difference? I also want to get the oil changed. Would it be best to get this done after the service?

Thanks again!

86 560SEL said: do I need to have the following checked/replaced:
chain, tensioner, rails, and guides?
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You should replace everything once you have opened up the engine...the aditional cost is very low to do the complete job. The $700 estimate you mentioned probably includes everything....the lower estimate probably does not.

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1986 560 SEL (159K miles)

Thanks. I am going to double check on that and have it done ASAP.

I was browsing e-bay for other 85' Mercedes and discovered this 85' 380SE. Wouldn't you know it - something with the timing chain/tensioner/rails went bad. This one has a hole in the left valvecover. (see photo of that cars engine) It has 336K. I wonder if anything had ever been changed on it.


Scary to say the least.

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Must have happend at higher speeds. Usualy when the fail on start up the engine just stops.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I have seen that happen several times. Very scary.

A good MB independent can tell you if the chain and guides have been replaced by looking at them. The guides will be dark brown if it has been a while since they have been replaced.

You might get some of the electrical connector things (plastic) and have them on hand just in case. They are so brittle and will break when disconnected from items before removal. They are cheap (around $2 apiece from the dealer) and are well worth the investment. If the valve cover gaskets are brittle or leaking - may as well get those while you are at it. Don't forget the brass crush washers.

You may as well have them change the coolant while they are at it. Be sure to use MB or Zerex G

This is fairly common, the chain rips the valve cover, there isn't much space there and the covers are thin. While collecting valve covers to polish, I found several cracked LH covers (right at the bulge for the gear) - and never a cracked right!

__________________
86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

Thanks. I called the last shop that I needed to call. He said he could not give an exact estimate without looking at the car, but it would be "big bucks" if it needed chain, tensioner, rails and guides. I am guessing he may refer to $500-$700. as big bucks? Hopefully he was not referring to $1000 or more. This shop is supposed to have 38 years experience on Mercedes repair. He said that more than likely @ this age and mileage that it has been changed and "upgraded" to a "double roller". I told him it was a 85' 380SE. He is not referring to it having a double chain is he, because it is my understanding that it came with a double chain in 85'.

He said he could check it to see if it has been changed for $65. He asked if the car was making any noise or anything that made me think it needed changed. He seemed to act like it was not a big deal. I just told him that the car had 263K, was 20 years old and I had no clue as to when or even if it had ever been changed.

I think I will call the other shops back to get more details.

It scares me that he has been a MB mechanic for 38 years and does not know that the '84-'85 380 model cars came with a double row chain. I think I would shop around more for someone to do your work. $65 is a lot to take off one valve cover to see if the timing chain is a double chain. Sounds to me like he wanted to make a fast $65 - if he is knowledgeable. If it is an honest mistake then maybe he is slipping or forgetful. Either way, I think I would check out another shop.

Thanks. Yeah, it bothered me too! I called the other shop "Benz Haus", that I KNOW has been in business for many years and has a good reputation. I spoke to the secretary initially and she said the guides were only about $3.00 each. She said the labor on changing the rails was much more expensive to replace. I did not know that extra cost or work about the upper rails. I was thinking it was going to be only a minimal increase in the price, obviously a lot more work is involved.

I wanted to know the cost of replacement on that and she transferred me to one of the mechanics. He said he has been working on these cars for 15 years. He said personally that unless it was making a noise then he would not change the chain or the tensioner @ this time. He said I should still try to obtain some of some service records from the original owner, but obviously I do not even know who that is.

I told him I was unsure about the rails or guides. He said it was not as much as a concern as the chain/tensioner. He said if it broke, it was not as high of a chance of engine damage, as if it was the chain/tensioner. He said if the chain or tensioner broke, then it was severe engine damage, which I knew.

I know there is a possibility that I may be sorry down the road if I do not change it right away.

Oh, one thing I forgot to mention is that when I was looking under the hood yesterday, I noticed that the driverside valve cover looks to have been replaced in the past, as there is NO oil residue whatsoever on that valvecover, whereas there is minor seepage on the back of the passenger side cover. When the chain is replaced, does the driverside valve cover have to be removed? I am wondering if this "newer looking" valvecover gasket may be a sign of a timing chain replacement. It has 263K, so I imagine that it was changed at least once, or it would be rattling like crazy by now?

Here is a photo I took yesterday of that area.

Thanks in advance for any input.

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