squeaking sound: idler pulley?

Yesterday I installed a new battery. Just for kicks I started the engine and listened to it until it warmed up. I could distinctly hear a sort of quiet squeaking sound. Definitely coming from the right front of the engine. On the right is the AC compressor and one of the idler pulleys. The noise seems to be coming from either one of these. I know zilch about AC compressors. Do they squeak when they start having issues? I'm going to replace the idler pulley tonight because they're cheap and easy to replace. But if it still does it, should I be concerned if it is in fact the AC compressor? Where I live it seldom gets hot enough to need it. But someday I'll probably move back to the South, thus will need it.

 

Idler pulleys usually make a grinding or wearing noise. I've yet to come across one that squeaks.
Have you gone through any deep mud or dirty water lately?

 

What engine do you have?

I know on the 3.4L - the A/C idler pulley goes first since it's the lowest most pulley on the engine and always gets blasted with mud/water.

I'm not familiar with the other engines...but YES, the bearings in the pulleys can squeel & squeek when they're going bad. Sometimes they'll squeel/squeek up until the engine warms up (the grease that is left inside the bearing warms up & distributes itself = stop squeeling).

The best thing to do is take off each belt and manually rotate the pulley's by hand. You're feeling for any irregular spin, rough spots, wobbling, etc. You're also visually looking for rust looking dust in the general area also.

On the 3.4L - there are 3 belts that operate the A/C compressor, Steering pump,& alternator. Each one will have a pulley/bearing. The A/C has the additional idler pulley/bearing.