My serpentine belt and tensioner were replaced in October of last year, after the belt broke. In April I took my car in because it was squealing, loudly. I was told the serpentine belt was too big and so it was replaced once again. Since that time I am still dealing with ridiculous squealing and reduced power when taking off in first gear. I am planning to take my car to the dealership, soon, and get the issue addressed but I was wondering if anyone has any suggestions as to what the problem really is and what I might be looking at as far as repair cost.

 

Tough diagnosis from here. If I had to track down something like that myself on my car, I'd start with an automotive stethoscope to see if I could hear if the idler pulley, alternator or AC were beginning bearing failure. Maybe remove the belt and make sure everything turns smoothly without dragging.

Don't pay much attention to me. Other forum members have much more experience with MINI's and the most common types of failures. Let's hope it's not the alternator, the OEM one is over $550 without installation!

Edit: PS -after belt breaking was the crank pulley also replaced, or at least inspected?

 

I'm really not sure if it was inspected. I know it wasn't replaced. I definitely hope it's not the alternator. I just dropped 2 grand for clutch/flywheel/motor mount/slave cylinder replacement.

 

Have you looked a the side of the sc pulley....sounds like an OEM belt was used as replacement with a smaller aftermarket pulley....
Stock pulley is hot pressed, usually black one, no bolt holes.... Aftermarket varies...but usually as a number...such as 15% or 17% are the most common...
A 535 length belt is the most common with either of those.... Some folks are using a 532 with the 17% ....a belt costs about 25$ and takes maybe 5 minutes to change...plus removing and rebooting on the pax side wheel....

 

All the parts came from MAG MINI of Dublin so I'm assuming all were OEM.

 

A new, unstretched OEM belt will work OK for a short time with a pulley...then start to slip and squeel, and may shread and fail...
Early on, some folks used the shorter JCW OEM belt with pulley, but the same issue would happen...so shorter aftermarket belts are used if the car Has an aftermarket pulley... Like many gen1 cars....

 

Ya I would make sure you have the right size belt.