Chirp sounds - Tension Pulley or Idler Pulley?

[3000GTCSULB]

Would the Tension Pulley or Idler Pulley cause a chirping sound at idle? These are the only 2 things I didn't replace last year when I did the 60K and suddenly I'm getting a chirp sound.

Thanks.

[DocWalt]

They could. I'd check the belts (alternator & p/s) first though.

[CoreyB]

Either one could do it. Disconnect the alt belt, then the PS belt, that will help you narrow it down.

[MADMarc]

...Or hold a pipe to the pulleys and your ear to listen to which one it is coming from.

[MR2]

well, I've noticed that a lot of new belts we're getting here in Australia are making the squealing where they use the glue to join the belt (or whatever substance you want to call it at the join) so my bets on the AC belt and probably as it goes around the alternator? is it a constant squeal or just the occasional chirp (so once per belt rotation or once per idler rotation?)

[BlackStealth]

My OEM crank pulley chirped like crazy before it separated into two pieces. Fortunately for me I caught this in time.

[3000GTCSULB]

For Posterity.
It ended up being my idler pulley.