Saturn SW2 Noises

1998 Saturn Sw2 My Saturn Has A Loud Squeal On Start-up, On Cold Mornings. I Realize It Has Auto Belt Tension. What Might I Look For

I Changed The Idler, Tension Pullies And The Harmonic Balancer And Still Haveing The Rattleing Sound Only When A/c Is On And Car Is In Idle...

My Saturn Drives Very Smooth And Continues To Give Good Gas Mileage. However, At Idle There Is An Intermittent Rattle In The Engine...