'05 MCS with 163k on it, its been well taken care of by the first owner and now myself (it spent 2 years with a second owner though). I'm not sure what the symptoms of needing a timing chain replacement are, and want to make sure that I don't screw the pooch and damage the engine, which runs great as well as the S/C. I'm just a wee bit leery since its got 163k on it. Oil's been changed every 5k miles since new, but its also been AX'd most of its life as well as use as a DD.
Just looking for some input from knowledgeable sources.
TIA,

 

Here is a quick video that has the sound to be aware of ... generally the chain itself doesn't fail, it is the chain guide and /or tensioner that fails... and if it/they do, the timing chain can jump a tooth or two on the sprocket and then it becomes a catastrophic failure ... <insert sad face where>


Motor On!

 

I replaced just the tensioner on mine recently. I bought the car with about 90k miles on it. The symptoms were that It would be noise-free when starting the cold.....but if I started the engine warm, the chain would rattle for a few minutes before tightening back up. This is a pretty typical symptom of a failing/sticky tensioner. Luckily, changing the tensioner on the R53 is pretty easy with the passenger wheel removed. Clearance is a bit tight, but it is doable. The tensioner is also cheap.

My advice is that if you have chain noise, replace the tensioner first and see if it resolves the issue....and if it's making noise, don't wait around to replace it as it can result in broken guides or jumped teeth as described by JABowders above.

 

Thanks very much, That's NOT a noise that I hear (Thank God), but its definitely one that would get my attention instantly. no rattling at startup hot or cold, just a ticking when really cold. That video was perfect.

 

 

Honestly, it's hard to say, there have been little to no failures with the chains themselves, even up to and above 250k.
​​​​​​There have been far more chains changed because of engine rebuilds or PM fears, than from any type of actual chain failure.