This started happening a couple nights ago. It was a slight mechanical hitting grinding sound but very faint. I would happen regardless if it was idling or under power. I check pulley tension and it seems fine and I topped off coolant levels. Then driving to work this morning the normal S/C whistle became significantly louder and thens a slight tick/knock when it idols. The video shows what I’m talking about. Gods of S/C s2k forum please bestow your knowledge upon me so I don’t blow up my favorite car ever. If the video doesn’t post let me know, I’m posting on mobile

 

no video in the OP

 

added the video link

 

Id be suspect of the blower bearings. Pull the SC belt to help verify, if the sound goes away you know what to hone in on. If that's where the noise is coming from after testing, spin the blower by hand, see if it doesn't feel smooth anymore. Pull the filter elbow and inspect the blades, see if any shaft play, look for signs of oil, anything that would help lead you to blower/bearing failure. If the noise is still present after removing sc belt, then you know to look elsewhere, like possibly an accessory or serpentine belt tensioner. Pull the serpentine belt and run the car for a moment to test verify this.