On the advice of some wise people on this forum, I wanted to start a thread to get some guidance on timing chains for the 300 SDL (I have the 86 model, but the people with the 87 model might be interested as well). I have recently purchased one, and I kept reading about the timing chain needing to be replaced on the the "diesels" at 100k. So, I talked to my dealer about it and it costs $500 to have it done (pretty reasonable to me as the chain is about $200).

My question is, with 154k on the clock does the 300 SDL need to have the chain swapped out? I guess I am just too new to this as I don't understand much beyond the 126 chasis identifier and the fact that the car is diesel.

Any suggestions on how to check the stretch or replace the parts that need to be replaced?

Thanks,

Tom

I have a 603 with 400K miles on the original timing chain...

I have a 617 with 300K miles on the original timing chain.

Usually timing chains give some "notice" when they are about to fail. They tend to get louder.

just my 0.02

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1984 Euro 300SDC, (4spd standard)
1986 Toyota Landcruiser Diesel HJ60 5spd X2

Gone but not forgotten (some sold, some stripped)
1983 300 SD, 1985 300 SD, 1983 240D, 1986 300 SDL, 1985 300 SDL, 1983 300 D, 1984 300 D, 1985 300SD, 1987 300 SDL, 1983 300 SD, 1985 300 TD Euro, 1983 380SEC, 1990 300 D, 1987 300D, 1982 300D, 1982 300D, 1994 E420, 1987 300 TD, 1987 300 D, 1984 300 D

The only reason to replace a timing chain on a 603 is if the elongation of the chain beyond 4 degrees.

There is no set time or distance for replacing the timing chain.

It is recommended to be checked periodically and replaced as it wears past a certain point. That point is open to debate. it is also open to debate wether to change it out or add a woodruff key.

I put a 4 degree woodruff key in when I first got the vehicle about 2-3 years ago. It's been at zero degrees ever since. When will I change it? When it stretches another 2 or 3 degrees or so.

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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Thanks everyone, it looks like check/recheck and change later.

Now, two more questions about the 603 motor (I learned this is the one I have today, so now I know two pieces of MB related jargon about my car ):

1. Does my motor have the plastic guide rails that blow up and cause "catastrophic engine failure"?

2. How do I detect the rattle from all the other noises made by a diesel? I would hate to have to say "so that is what the rattle sounds like right before the timing chain blows" .

LOL...someones been telling you some tall tales. Just check them when you check the chain.
Actually they were probably talking about the vacuum pump.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41966

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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(='.'=) This is Bunny. Copy and paste bunny into your
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Actually, someone could tell me the flux capcitor is not getting the 1.22 gigawatts and that I am in danger of being sucked into an alternate universe.

Man, trying to keep up with people who have been working on these for some time is like learning spanish by having English interspersed in the conversation.

So, the timing chain guide rails explode becasue they are plastic and the get old, right? Is this only on the 617 engines (Yeah! another piece of Jargon!)? Or do I have the same guides?

I am a bit embarrased to say this, but I normally don't check the chain. I have not had a car that needed even minimal work since college. Either I took a bath and bought a new one, or I went without (lived in the city and had a motorcycle). I can have the dealer check it, but I bet that costs $$$. Since I cannot get the shop manual for this car, is there a write up specific to the 603 turbo that I could use? I did search, but I am not sure if I am using the right directions.

Thanks for all the help!

Keep digging for the proccedure it's out there. It costs about 25.00 to buy a dial gauge and stand from harbour frieght to check it yourself. It's always a crap shoot on unknown engines.
Perhaps a previous owner has already had it changed. Or perhaps it is still has very little wear. Or perhaps it is worn to death and has damaged your sprockets. Or somewhere in the middle.
They develop a very sharp points on the sprockets when chain has really excessive stretch. Check your chain every say 40 k and especially make sure the guides are not wearing through. They are the potential culprit in reality.
The dial gauge is not an absolute neccesity to set up the front wheel bearings after a bearing repack either. Yet mercedes recommends it. Anyways whats 25.00 in comparison to what garages do to you for a dial gauge if you do not own one. I still feel in general the state of the chain reflects the changing of the oil and it"s frequency well. Exception might be excessive miles though. I mean a lot of them too. Or almost never getting an oil change and filter. This chain is a robust design in comparison to even some other mercedes designs. You probably could lift the whole car with it.