I am able to replace the alternator on my own but I want to make sure that's what the noise is. Noise goes up and down depending on rpm's. No extra noise when turning. I saw a mechanic today and he put a stethoscope up to the alternator and he thinks it is probably the alternator. Seeing that there is so many other things it could be I don't want to buy a new one and still hear the noise afterwards. I forgot to tell the mechanic that the battery light started coming on shortly after the whining sound started and also that there was a plug-in cooler in the front of the van that was the start of the battery light coming on. All three things happened around the same time. Whining noise, cooler plugged in, and battery light coming on. I'm almost positive it's the alternator, anyone else?

 

Sounds like the alternator to me.