A170-is it prone to timing chain issues

[xselseven]

Hi

I just bought a 2006 a170 **********e, and now I find that it has a tappet like sound all through the range, but especially at idle, and when driving at 4000rpm.
I have not listened with bonnet open, and someone revving the engine.
I did stand there and listen to it idle, and the engine is juddering quite a bit.

My research so far indicates it could be hydraulic valve lifters, but that does not explain the bucking engine at idle(or maybe it does)

Further research indicates it could be the timing chain, and or tensioner.

I am unsure how to proceed to diagnose what exactly is causing the noise,
apart from one post said take the oil filler cap off,and listen for louder noise.

There is also the idea of wynns valve cleaner, engine flush, and a mixture of diesel with oil, or ATF with oil, and see if that alters the sound.

 

[4johng]

Hi,

Only the other day on the slk forum , a member said his R170 230 chain had broke , the first I had heard of ,and to begin with nobody believed him.

They can be a little rattely mine is with 89000 miles. However they are prone to worn chain tensioners, and without hearing the noise this could be the place to look, but has I have said it is very very rare that you hear of one going and when it does it is usually caused by a worn tensioner.

Regards,
4johng