1st Gen R53 Cooper S Most liked posts in thread: Supercharger help? :D

Many SC rattle a bit...the lobes are very tightly fit...can sound a bit like an eggbeater....
The "bad" sound is more like a draggly chain sound....
One tip...SC rattle and throwout bearing rattle is sometimes confused...
So sit in the car...push the clutch in...see if you sound goes away...if so..its the clutch/throwout bearing...

 

If the SC is low enough on oil to have metal on metal unlubed gears, then the seals are bad...just changing/adding oil, about a 5 hr job (for a pro, more for a diy'r) plus about $50-100 in gaskets+lube would be a waste IMO...
If you are going to dig deep enough to remove a SC, IMO, you should get it overhauled or exchange it...I think I have seen more threads on post diy "fixes" having to do with vac leaks and other issues here than it has saved folks...
If it is a SC gear issue it will worsen rapidly...but many rebulders INCLUDE the PTO rebuild in the basic cost...they SHOULD since this is WHY many SC fail....and while you are at it...swap the WATERPUMP too...

But enjoy your car, have fun, and give it some time IMO. Many folks go temporarily OCD reading about issues on forums with a new car...
Sure some cars are sold cause issues might be looming...but often folks get worried about a new car...

 

Use a long screw driver up against the nose cone to listen to it, see if its the supercharger for certain.

 

Unless it's really bad/loud/noticeable, you probably have plenty of time, I drove mine for nearly 20k before I changed it, just keep an eye on it until you don't feel comfortable driving it. As mentioned before, watch your temp, the noise is most likely the W/P gears, (99% of the time) and yes the sound will transfer to the nose cone, but because this is normally the issue, besides overheating, you won't damage your motor itself even if you drive it until it drops, any metal shavings will stay in the housing.

 

change the oil in the thing and get another 50k miles out of it. Not too hard to do. Takes a day of tearing into it if you've never taken the front end of the car apart. Watch ModMini's SC oil change and front end service videos on Youtube to give yourself some confidence that you, too, can do this in your own garage. Other than the #%@! intake tube it was pretty easy. Having the right tools and wiggle extensions helps. I'll be changing my SC oil every year from now on.

While in there, fix the usually leaky crank position sensor O ring and dip stick O-ring, replace the water pump, and then bolt it all back up.

 

Just remember, while the '05 and later SC's are slightly mite desirable because of having coated rotors, they still suffer from the same issue, anything I've 125k or so will still give you the same problem, if you can't do as "Fish" suggested, just start putting money side for a rebuilt unit, you'll be looking at at least another 100k out of one of those.

 

Two questions...
When you rev it to near redline...does it squeal a bit?
I'm wondering if you have a belt that might be too loose...and
What size belt do you have?
I generally suggest a 532 with a 17%, a 535 with a 15% if you have the stock size crank damper...
A failing idler should sound like a bad bearing..whirr...
Guess it's possible the little gas strut on your new damper failed...infant mortality....

 

There are a bunch of aftermarket and OEM vendors of the belt tensioner for the Mini, some apparently better than others judging by posts over the years...always buy from a reputable dealer...and the idler pulley is an often overlooked item. I replaced mine at 95k miles although it had no symptoms...when I removed it I noticed it was certainly worn compared to the new one that replaced it...I should have replaced it earlier I think.

As so many things on our Minis, better to replace before failure...cheap insurance to keep you off the side of the road...

 

The idler pulley is easy and cheap to replace. That's one part I'd almost recommend just throwing at the car to eliminate it from the list of potential noise-makers.

A note on diagnosing a supercharger: the M45 charger is a very noisy piece, even when brand new. If you're using a stethoscope or pry bar to listen to bearing noise, you might be fooled by all of the noise.