I have a squeak in the alternator of my 2004 Optra. i was talking to a mechanic and he told me I would have to replace it or the bearing in the alternator. I was just wondering if anyone could tell me if a different alternator from a pontiac or other chev car would fit, like from a sunfire or cavalier. Any help is appreciated. Thanks

Most scrap yards have a cross reference manual. If you take it with you they will match it up for you.