had problems before, lights would dim and car would sound like crap when im stopped at a light, with the voltage jumping, along with the alternator humming on and off in conjunction with the lights dimming. fast forward to now, new battery, alt, serp belt and no more dimming, but sometimes when im at a light i still hear the alternator, its not loud like before but i can still hear it, is that normal? as soon as i tap the gas the noise stops.

 

anyone? also noticed it's more noticeable when headlights are on.

 

Are you 100% sure it's the alternator making that noise? You sure it's not another component?

If you are sure it's the alternator, try taking this one back for another one. It's possible you got a bad one. Unlikely, but possible.

Otherwise, if the car is working fine, I wouldn't worry about it too much. Maybe take it to a shop and have a tech full field it and compare it to the max output ratings on Alldata.