This is my first post, but I've been reading for quite a while. My wife owns an '05 cooper S, and earlier last month it started making a rattle/knock at idle that went away around 1,500 or 2k rpm. I had her park it, and started looking at it again last week. I was sure it was going to be the supercharger that was failing, but after some stethoscope work decided it was more likely timing chain or idler pulley noise. I took it to a non dealer shop this week and they determined it's the timing chain. My wife just wanted it fixed so we went ahead with having the parts ordered. Now I'm wondering if shops/dealers ever just replace the tensioner, and not the whole thing? The cost for everything is about $1200, and then I don't have to do it, but reading more posts about this issue it sounds like some have just replaced the tensioner. BTW, it's the original timing chain/tensioner, and it has 120k miles on it. Good preventative maintenance, or should I bug them to just try replacing the tensioner? How likely is it that the chain is stretched/damaged as well?

 

Yup, with only 120k most likely is the tensioner, tensioner works on oil pressure, thats why the noise subsides as rpm builds, it's only a 20 min. Job max for someone whose done it, so expect the 1hr min. + part.

I'd be willing to bet that if you looked back at "timing chain" replacement posts almost all have been a part of PM not from actual chain problems.

 

Another question...or more of a suggestion....
You might want to try a different oil...maybe a 5w-40, as opposed to a 5w-30...both are recommended for gen1 cars by mini....Will help you with oil pressure.... Some oils, like Mobil 1 can get thinner after initial filling, before thickening back up after a bunch of miles...

 

So is the concensus that replacing the chain and all parts beyond the tensioner is just a waste of $$ at this point? or do chains stretch to the point of needing replacement at some point normally? This may not be something I can request at this point (just doing the tensioner. They likely have already started tearing into it), but I'm just wondering if I'm being foolish to have them get it all done now. From my searches on this subject, it sounds like some have done the tensioner but still had noise till the chain was replaced. I'm just wonding how common it is.

As a side note, I called a mini-exclusive repair shop in Minneapolis to get a quote on an SC replacement (if, in fact, that was the problem), and he said he really doubted it was an SC problem because they rarely see failures at their shop. I got the impression from this board and others that it was pretty common. ???

I'm using mobil 1, and it seems pretty thin.

 

Chains in a gen1 are normally good for the life of the motor unless abused by running very low on oil, very long change intervals (most folks who want to keep mini's longterm use 7500 mile oil changes or less), etc.....
A few folks have had the tensioner get weak....try the simple, cheap fix first IMO.

 

+ the tensioner & chain are in 2 different places, not like you'll be tearing something apart again.

My chain has 212k on it.