After a disaster with the timing chain jumping a few teets on the cam
sprocket, I have replaced the chain, the chain guiders, four exhaust
valves, etc. on my 1981 380SE (an European version with double chain).
Now, how to I know if the chain tensioner also needs to be replaced?

pej
--
Per Erik Jorde

The only reason chain jumped is because the tensioner went bad and chain
stretched... so just change the tensioner.

"Tiger" <tiger0002 (AT) hotmail (DOT) com> writes:

The chain jumped because a piece of the plastic guide rails was stuck
between the double cam sprockets. But you're probably right that a bad
chain tensioner may have been the primary reason for this malady.

I still would like to know of there is a simple (as in DIY) way to
check the chain tensioner. I have another MB too, and it is well beyond 300'
km....

pej
--
Per Erik Jorde

I personally don't think it is worth testing it. Think about it... how many
years did you get out of it? How many miles or kilometers? Plus, timing
chain and tensioner is supposed to be changed roughly every 150,000 miles.

When you divide the miles or years from price of the new tensioner...
$63.70... don't you think it is cheap enough?

Plastic guide breaks only because timing chain was slapping against it... so
chain stretched and weak tensioner caused it.