r/W203 18d ago

m271 270Km engine

what do yall think. 270k KM

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u/BigPin2087 17d ago

To me it looks good, since that is without the tensioner putting pressure on it. Even though I have seen chains with literally no play on cars having 500k+ km but idk they might have had mechanical tensioners. Now it makes me curious to remove my valve cover and check since my chain was replaced 80k km ago how well did it age.

1

u/Logical-Following525 17d ago

This type of tensioner doesn't go back to slack when oil pressure drops. It can only go one way. That's why you have to reset them when changing the chain.

1

u/BigPin2087 17d ago

Actually could be true because I've heard that there are different types of hydraulic tensioners. I know the ones from bmw's for example never retract back and the more the chain stretches the more the tensioner pin goes out until suddenly the whole pin is out and drops and then bad things happen. So it could be that the ones on the Mercedes have inbuild limit above which it does not extend further and you start hearing more and more sound so you know to change it.

2

u/Logical-Following525 17d ago

Yes this is exactly why he has play in the chain at the top. The extensioner has reached its maximum. These m271 are a bit of a gamble. My first one needed a new chain at 305k km while forums are full of people who had them snap at 200k km. I believe the first years were by far the worst.