So recently a noise has caught my attention and has been getting louder. It happens when the engine idles at its lowest which make me think its a pulley. Its not the belt and its not idler pulleys (I jumped the gun and bought new pulleys and serp belt and replaced them). Its like a chirping that you would here when something is rubbing wrong like a bad bearing in a pulley. It gets louder when the A/C is engaged which leads me towards the compressor clutch pulley... but when i was in there replacing the idlers, I accidentally spun the fan and there was a slight chirp that happens when the cooling fan pulley rotates slow. I still wonder why the A/C on would make it louder other than there is an extra load on the loop. What do you guys think?