Engine related question to my 380SEL

I have a 380SEL w/ only 51k miles. It is a 1983 model and still has the "single timing chain" Now, I hear some sort of rattling noise when I start the car. It doesnt go away at all no matter what you do, Rev it up shut and turn off, etc... It sound like soda cans rustling on the street but it isnt loud at all. You can only hear it when it is extremely quiet around. Im worrying that it is the chain and it will break on me. What shout I do?? Is it the chain making the noise???

Me again...

I also have a 420SEL w/ 143k miles and I have no clue if the chain was replaced at all?? I know it has the dual timing chains but should I change it although I don't even hear anything?? MY engine is a quiet as it can get.

[RKreutzer]

Hi benz-vettes

it's not so much the chain as the tensioners that need to be replaced at certain intervals/years. The chain is checked for stretch at the time the tensioners are replaced and based on the stretch a decission is made on the chain.
Do a search, there is plenty in the archives.

Based on age, I would have both cars checked out. I got new tensioners on my 87 420 with then about 45,000 miles on it and the mechanic reported some of them already partly broken.
I believe stevebfl has given a recommendation when to replace the tensioners based on miles and age.

Good luck

Reinhard Kreutzer

[MikeTangas]

Even though I can't find proof in the 3.8 maintenance schedule I believe the simplex chain calls for replacement at 30K intervals. The simplex (single row) chain doesn't stand up to wear like the duplex chains.

EDIT: at one time the dealers were doing the duplex conversions, but that campaign ended long ago. Apparently all of the parts can still be had and the conversion can be accomplished...at a price. One member of the board did just do a simplex to duplex conversion in the past few months.

[stevebfl]

The single row chain is a bomb waiting to explode.

I think we discussed your 420.

The actual parts that fail in the 116/117 chain system are the chain rails. I would not call them tentioners as they do not touch the chain in normal operation. There are two rails in that motor that are tentioning rails. Neither causes problems in normal mileage (up to 300k).

Hi, thanks all. I will do more research on the 420 and I will get both my cars checked out.

THANK YOU