Have a 06 Pacifica. Have a whining noise coming from the engine compartment only when I have the a/c turned on. Is it my compressor going out or is one of my pulleys going out. The belt is new and only about 5 months old. Does anyone know what is could be?

 

well i dont like to mess with a noise online because well its online..
So common scene rule all the items that the belt is moving aka pulleys and such they are moving any time the engine is running regardless of the ac being on or not.

There for more then likely not a pulley.
Now the ac compressor could be screaming yes because once you turn it on the clutch closes and turns the insides of the compressor the pulley for that is still turning the same as it was before it was turned on.

Your can put your hand on teh compressor and feel it if its making noise or not I know sounds fully but a noise is only a vibration that a human ear can or cant not pick up.

 

As Chrysler Tech stated it's hard to diagnose a noise online just by description. Even with a video it can be hard. With multiple idler pulleys, tensioner pulley and drive accessories it's a process of elimination. I was lucky in finding the source quickly. Since yours is only making the noise with the A/C on it could be the compressor or pulley/clutch could be the source. But you are also adding load to the drive assembly with the A/C on.

My '06 started making a whining noise not long after I bought her. I thought it would be one of the idler pulleys or the tensioner since it did it all the time while running. The belt looked fairly new with no visible cracks. I had bought an upper idler pulley as that seemed to be where the noise originated. The bearing was rough but the sound presisted. I bought a new belt (Continental since no one had a Gatorback in stock). Installed the new belt and the noise went away.