One day I heard a whining noise from my 05 Chrysler Pacifica. So being a little bit mechanically inclined and changed out the power steering pump. When I got done and started it up, everything was working properly but the whining noise was just the same as before I did the pump job. I figured maybe it was a bad power steering pump so I took the power steering pump back out replaced it with another one, started the car up and sure as the day is long the whining noise was there just the same. Now I don't have a stethoscope for a car so I took a big steel rod put it to each one of the pulleys on the belting system (which is where the noise is coming from (front end where the belt is about 6 or 8 inches below the power steering pump), and it seems like the noise was loudest when I put the rod to the tensioner pulley. Could it possibly be my tensioner pulley? I tried to look on YouTube and found 50 people with the same whining noise problem that I have and nobody seems to have answers. I have called Chrysler Jeep and Danbury Connecticut. And they say that nobody's ever called them with that problem, I even called a couple auto mechanic shops and they said that they've never heard of the problem. Can anybody help me. I would be in your debt and have a big IOU to the first person who can let me know what this actually is. Thanks for your time guys

 

I have the same thing, does your serpentine belt deflect more than about a half inch when you press on it? Feel a little loose?

in my case I stretched mine out taking it on and off several times, I didn't have the 3/8 tool at first and pried it loose at the alternator.

there are about 3-5 possible reasons, especially since you just changed the steering pump.

TRICK, put bar soap, like ivory,dove,lever etc, ONLY on the SIDES of the belt, not the back or front. Sometimes it can squeak there.

1. Stretched out belt.
pop a new one on, keep the old one with your spare tire for emergencies

2. Bad battery
test battery with multi meter, should be 12.3 volts with car off, around 14v running. If the battery is below 11.5 it's bad and the alternator will work too hard.
3. Failing alternator
Test with multimeter on battery terminal's with car running ,should be at least 13.5, if lower you will need an alternator soon. Try turning on everything, lights, heater, radio etc, squealing get very loud?
4. Bad tensioner
acts the same as loose belt, replace 15mm

betcha it's just that your belt is getting old, I would put on a new one, doesn't hurt. Also there are belt anti squealing sprays you can use, but I don't trust them

be sure to let us know what it was!