I have a 2004 Honda Civic VP 1.7L, I just replaced the alternator and got everything hooked back up. everything seems to be working great, but now when I turn on the AC I get this whining sound, it only happens when the ac is on, I can drive and such no problem, I can turn on my blower and it works fine, the sounds only happens when I turn on the AC, it gets louder as I accelerate the engine, and again the sound is only when the AC is switched on. the belts seem tight, with about a half inch give, and seem to me like if it was a belt issue it would whine even if the AC was off... any ideas?

thanks-

 

The AC Compressor clutch, or the AC Compressor itself may be having issues. However, did you replace the accessory belt, when you replaced the alternator?

 

I did not replace the belt, it seemed fine, no nicks or tears in the belt, all the groves were good. the ac worked excellent before I replaced the alternator, ill check the belt again in the morning but it just seems that if it was the belt then even with the ac off I would get that whining... so frustrating... I hope it is just the belt, that will be way easier and cheaper to replace/fix.

 

when the ac is on it adds more pressure to the belt so it's likely that belt is too loose

grabbing the belt with your index finger and thumb in the longest side of the belt, in the middle of that side, twist it, it should only twist 90 degrees