Hey there. So my air conditioning unit under the hood is making noise when the ac is NOT engaged. My friends dad who is an american car kinda person said it's the pulley? Can someone explain how the ac unit works? Does he mean the ac clutch? When the clutch isnt engage it spins freely, im assuming its a bearing on whatever is making noise cause i can hear a noise like that when i listen to it thru a tire iron. I need more clarification so i can figure out what to buy to fix the issue. Thanks!

 

The bearing is part of the pulley which is part of a clutch set. You can either replace just the bearing or buy a clutch set. But if you get a new clutch set you will have to adjust the air gap. There are howto's on youtube for either approach.