On my 01 ML320 i am hearing some noise from the timing chain but only on low idle. When I am driving or give it heavy gas I do not hear it. When I open the oil cap you can hear the tensioner moving around.

The car has 140k miles. Does this sound like the entire timing chain needs to be replaced or just the tensioner?

 

Timing chain should be fine for the lifespan of the engine. I would say you need to replace the tensioner only but if someone was driving it crazy hard, chain could be stretched out to the point that tensioner can't make up any tension in all the way out position.

 

I changed the tensioner and its still making the noise. Still sounds like its coming from the timing chain.

 

I have exactly the same problem under 2500 rpms, what was your solution to your problem??? help me

 

was it a slight ticking noise? if it is, its just something that is very common. valve adjustments. over time, the valves gets loose (not a lot) and causes this slight problem.

 

just bring it to the dealer, tell them you want your valves adjusted and it should go away (the problem)