When I turn on the A/C it makes a high pitched screeching sound. I've had it serviced FOUR times under warranty and now it's back yet again. I'm going to bring it back to the dealer when I get a chance. Anyone else had this issue? If so, what was causing it? I know they've replaced the coil and clutch along with a few other things. The A/C blows cold but the sound is just annoying.

 

Belt squeel. I would check the belt tensioner and the belt for cracks / dry rott. When the compressor engages it puts extra strain on the system, causing the belt to slip. If you have anything leaking oil (Compressor oil from clutch, Engine oil, powersteering fluid etc) onto the belt it could cause the noise too.

Either that or the compressor pulley is locking up causing the belt to be dragged over the pulley but that would probably make a burning rubber smell too

 

Thanks! I will mention that and have the dealer check it out. I think they've just been blindly replacing parts so far with out really having any idea of what's going on.

 

Either the Compressor bearings are going when the clutch engages or the belt needs replaced. You need to pop the hood with the AC on max and see if when it makes the noise if the compressor pulley (part the belt is on) still turns and if the clutch engages (part in front of the compressor that doesnt spin unless the AC is turned on). If they both spin I would say belt has an issue.

 

As stupid as this may sound, which part exactly is the pulley and the clutch. Here's my engine (sorry, I've honestly never paid any attention to any A/C components when opening the hood ha:

 

Er the belt spins the pulley which should spin all the time. The clutch should only spin when the A/C is engaged.