Hey guys, so I own a 2007 Cooper S, currently 25K miles. I bought it used and had it since July 09. Since then, it's been in the garage 4-5 times already. Luckily I have maintenance till June 2010, and warranty till June 2011.

Here's what I've been through since I bought it...9mos ago...
1. Transmission replacement, after I brought it in for some weird high-pitch noise.
2. Found turbo leaking during regular maintenance.
3. Clutch was acting weird (new transmission), multiple times of Sulphur odor (rotten egg smell) while driving on highway (didnt really rev up beyond 4.5K rpm) and had to drive with the windows down.
-> they found nothing wrong with the car. Could not reproduce sulphur smell.
4. Brought it back in due to sulphur smell. I had to drive a couple of times on the highway with the windows open (during winter/snow) due to the smell, and couldnt breath right. -> again "cannot reproduce problem, nothing wrong"
5. Brought it back to the shop due to multiple times of sulphur smell on the highway, and also the "overheating engine" indicator came on.
-> they found the water pump leaking when tested under pressure, and the coolant leaking. They still cannot figure out the sulphur burning smell.

When the sulphur smell problem kicks in, I really need to drive with the windows down, even during the rain...and I am really frustrated of hearing the technicians say "cannot reproduce problem, nothing wrong". searching online leads me to a bad catalytic converter, and I told them about this. They are currently looking into it, but it seems like they won't do anything about it until the technicians smell it. This problem occurs randomnly 3-4 times a month.
--> maybe it's due to the coolant leak? coolant burning off?

I thought Minis had good reliability ratings. Am I stuck with a lemon? or is it normal to have these problems to occur so early??? My old BMW had these issues after 7 years with roughly 80K miles...

 

my first guess is the catalytic converter. when they go south the sulfur smell will be there.

 

Sorry to tell you after you bought the car that the Mini does NOT have good reliability ratings, good defined by above average.

Sulphur smell is typical CAT so I agree with sequence that that may be a good place to start.

If the Mini dealer is near you, I would suggest that you drive there when there is a problem and have someone (anyone) come out to look at it immediately, just to confirm the issue. When it is documented, you can come back another day for service.

I had this happen on my p-car when they could never find the problem. When it has having problems, I just brought it in and showed it to any random sales guy and when he saw it, he gave me his card. Next time in, no questions.