Hi, my '75 280z makes a horrible squealing sound whenever you engage the A/C. If you set the climate control to vent or any other setting the noise doesn't happen, only when its on A/C with the fan on. I heard it could be the belt so I sprayed a generous amount of water on the pulleys and belt and the sound persisted. The noise gets louder and changes pitch when I press on the gas. If I get out and look at the belt when the A/C is engaged I can see the belt slow down/catch on something. I've driven it with the A/C on for a few minutes to see if it would ever stop but it hasn't.
At this point I'm kinda lost as to what it could be and what I should do about it. I'd love if you guys could give me some advice.