I have a 2003 Cooper S and I have gone through 2 alternators within 2 weeks. Something is blowing out the diodes in the alternator and I cannot figure out what it is. I checked and wire brushed all of my connections to ensure they are making good contact. Whenever I initially install the alternator it is fine when the car is idling. When I drive from work to the house I check the voltage to make sure the alternator is good, but it shows 13V, which is about 1.2 volts under what I would like to see at a minimum. I just checked it today and I know the Alt is bad again, and my battery light will likely come on tomorrow when I wake up for work. I am currently running the mini with a yellow top optima, and I have replaced the SC pulley with a 15% alta pulley. I've checked the wire run from the battery to the alternator and it all looks good. Has anyone ever had this problem? Somebody please shoot me a suggestion, because taking off the alternator on a weekly basis to get it checked is getting old, and the frustration is brewing deep within me! Thanks!

 

Is it a reman or a new one?

I had bad luck with a reman and went through 3 of them. Learned that lesson.

 

a faulty battery that is only accepting low/surface charges can cause this issue. I KNOW ITS AN ULTIMA-but i would start there. aside from that i agree with big-daddy-blue on the reman trash. get a dealer alternator and call it a day.

 

I had my old one rebuilt, but I think I will just take the hit and get one from the dealer. I'm sad that I will be out $180, but lesson learned. Thanks for your input. Does anyone know any place to get an alternator for a "reasonable" price since I know they are expensive. The lowest price I could find was $474... ouch! I have a feeling I'm up the creek without a paddle right? *sigh The things we do because we love our car. Thanks again for your advice.