W126 Changing chain
 

Timing chain has 10deg. of stretch.

So I've got a nice IWIS chain, new guides & a new rail & cover. I pulled the valve covers and all of the guides are pretty white-ish and not very worn - not at all the brown brittleness I was expecting. I'm thinking I may not even replace them, as just a chain roll-in would be much easier.

Do I need to change the tensioner as well? My MB CDs still haven't arrived, so I know squat about the tensioner - is it oil pumped?

There was no slapping or other noises before I decided to change the chain, so I figured I'd just back it out a little (using the small bolts) to make it easier to remove the guide rail & rail cover before I roll in the new chain.

Oh, and I decided to check the chain because I just bought car. 137k miles w/ broken odometer.

What model are you working on?

More precisely, what engine does it have in it?