One of the only way to check is remove the right valve coverceck for tension than mark the chain with a yellow felt pen or something than check the chain links on both sides and slowly spin the engine clockwise and check if any one of the links look of a different color.Usally they have a goldish color the new master links,and some time ago they actualu even came with c-clips to hold the master chain link in place.Keep looking also if one of the links are differently mushroomed.If you cant find any replced link or one that is different,than all i can say is GET IT REPLACED soon.If one day you are driving down the road and the car stalls or shuts of art idle,open up the hood and look at the right valve cover and if it is brocken or cracked than you are up for a 2-4 grand bill coming up.So change it for your safty and your piece of mind

We've been through this chain stretch thing several times here and in the techs only section. No one has ever come up with any documentation stating maximum degree of cam retard before chain replacement on the V8s. We've established a set of parameters by consensus. Pull both valve covers and rotate the engine until the crank is on zero. The mark on the right bank cam should be pretty close. That is the one on the passenger side. If the left bank or driver's side is late, rotate the crank with a 27mm on the pulley until the marks line up. If it is over 8* late a new chain is in order. If you continue driving with a streched chain, the whipping chain will eventually snap the inside rail on the left bank. The piece of rail will wedge in the teeth of the cam, stopping the cam, and causing the pistons to bend the valves on the left bank only.

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Sorry autozen,what you say is right but unfortunately it will bend both left and right valves.But what would you say the interval for the timing chain replacement is on the 116,117 engines and the 103 engines?

WOW. Sounds like the damage could be rather severe!

How about the 86'+ 300E models? I know of someone with that model and they were worried about it. How critical is this on the 300E? Also know of someone with a 81' 300SD. Will the valves also bend if it breaks on these models? Thanks!

Hey 86560SEL ,yes it is a big damage so get yours done.And with your friend ,the diesel defenetly needs to be done soon to.As of the 300e that is what this whole forum is all about.Everyone is saying that they last 300+ k.Well i say as not someone that wants to sell you somthing,but out of experience to replcae the chain on the 300.You will probally get some guts after my answer come on and say,No dont worry the chain is good for ever.Well let them say it,but i have been repairing these cars long enough to know better.Hey the chain might last 250 - 300 k but would you risk it for a 3 grand bill when the chain does snap.The job should not cost more than 400 - 500 bucks.it is save insurance like i have already sayed that this will not happen

Sorry,but I stand my ground. I've experienced a dozen or more of these rail failures on both the early 116s and 117s and the late 116s and 117s. I have never seen bent valves on the right bank. That cam continues to stay in time with the engine. the 103 chains have been discussed here and it appears they are fairly bullet proof as long as the car is maintained well

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ok autozen i think we dont need to go any further .you have your idea and i have mine.But unfortunately when you are driving at 80km/h and it brakes ,gues what both side bend.And ok lets say it was at idle and only the right side bends,would you only take the right side of or both heads.Gues what we would take both of ,and even if the valves are not bend ,the guids might be worn and the all famous left head gasket leaking.We would do all at the same time so the customer has a piece of mind drivind his 380,420 ,560 for another 200k without having to worry about it.

I don't disagree with you that to do the job properly is to servive both heads, but that wasn't the question. That is exactly what I would do for a client. The question is do you bend valves in both heads and the answer is no. Actually at this moment I have an 87 420SEL and A 90 420SEL in my shop with bent valves on the left bank and both were going less than 20 miles per hr. I have an 83 380SEC on my trailer with bent valves on the left bank that was doing about 80 mph at the time. I have an 83 380SEL that I'm parting out that bent valves on the right bank, because the oiler tube came off and seized the cam.

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Ok i guess you get the once with one bank valve bend.the last thing i will say i did get a 560 sel in about 2 years ago where both sides hit,and the damage was so severe that we had to replace the engine.and 4 days after that a chain broke at start up and only the right side broke.

Thanks for the replies. Most helpful.

I phoned one of the local Mercedes repair shops this afternoon to get an estimate on the replacement of the chain(s) and tensioner for the two models I am likely to purchase. One is a 85' 380SE (if we agree on a delivery fee) and the other is a 84' 500SEL. The lady got all of the info and phoned me back. The results are as follows:

For the 1985 380SE: $226. (tensioner and other parts), + $103. for the chain and + $196. labor. For the 1984 500SEL it is also $226. for the tensioner and other parts) + 112. for the chains and + 196. labor. Both are a little over $500 each. Does this seem reasonable?

There is another local Mercedes shop that I am going to phone tomorrow. I am unsure when the chain was changed on the 85' 380SE (which I am more interested in, because it is cheaper and they are willing to deliver). I talked to the owners daughter and she said she knew for a fact it was changed before, but does not recall the mileage and would ask her father. Not a big deal, because I will buy the car either way and if the miles of change are unknown, I guess I will go ahead and have it changed. Any other parts I should go ahead and have changed while it is apart?

I really like the longer look of the 84' 500SEL and the fact that it has the driver airbag option (which the 85' 380SE lacks), but I would say that an airbag system that old would not be that reliable? For $1500 less, I can live without the airbag I suppose and just depend upon the standard safety built into the 80s S-Class.

There is a LIKE NEW 88' 300E for $3000, with 114K, 1-owner miles here locally, but I really want the S-Class.

Thanks again guys/gals!

Those sound like reasonable prices from benz that you got.as long as they do the work proper.My dad has a 84 500 sel ,german version.I noticed driving it that it sure has more balls than the north amercan version.It looks good from the outside ,but to bad it is a piece od sh-t underneath.But as long as he is happy is all it counts..And believe those cars are build solid.Even with out an airbag you will be safe

Thanks for the additional information.

I want to clarify that price I quoted was from a local independent Mercedes repair/sales shop and not from our local MB dealer. No telling what they would charge.

As mentioned, I am pretty sure I am going to get this 85 380SE. The only thing I am waiting on is if the owner will deliver for a fair fee. It is 3 hours away. I cannot get away that far at this time. I am thinking that if it will make the 3 hour drive that it must be a dependable car, which it is stated to be. The paint is a bit faded, but it is a 100% rust free southern car, which is a plus. I had found several up north, but all had some form of rusting.

What's wrong with the underneath?

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Ok that sounds better,cause MB stealership will rape yo on most things.The independent shop...Is that a only MB shop or do they do other cars too?If they do work on other cars ,make sure they use good quality parts.What ever make sure they DO Not use any Meyle parts...

And autozen,that was a car built out of 2 or 3 cars, with bad quality work.Under the hood it is discusting,but my dad was told from a german body man that the flat black on the inner fenders in the way it was new.Well unfortunately the fenders should be the color of the car.I took a couple of door panels of to repair something ,again different color ,rust and all the nice quality of bad workemanship.On the outside it has the Lorenser Body kit on,and that is what my dad liked.The car is worth 3 grand ,and my smart dad payed 15 grand for it..You know the saying "an idiot is born every day"

Yeah meangrean, they only work on Mercedes automobiles. I think that is also the only models that they sell at the sales part as well.