Q: Whining Sound from alternator when cold start

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My Cherokee recently started making a whining sound when I start it up and when I accelerate (I'm not able to post the video I have of it). It mostly happens when it's cold outside. Once the engine warms up it stops. Everything handles as normal, haven't noticed any difference besides the sound. Recently got a new battery and starter. I replaced the serpentine belt and tension pulley about 2 years ago. The belt and all the pulleys look good to me.

The sound is clearly coming from the alternator. I've had alternators go out before, but never heard a sound like this. Is it going bad? I have the V6 so with all the extra space in the engine compartment it would be a very easy fix. But if I don't have to drop the money I dont' want too.

Ideas? Do I need a new alternator?

Here's the sound: https://www.youtube.com/watch?v=a-C64SgyvLo

My car has 155000 miles.
My car has an automatic transmission.

The whining sound is a sign that the bearings in the alternator are going out. This is a problem that will only get worse as time goes on. Eventually, you may also notice the alternator may begin to smoke a bit due to the friction caused by the worn out bearings. I would suggest having a professional from YourMechanic come to your location to diagnose and replace your alternator.

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