high pitch nose. . .

I finally started using the AC in my jeep (for the first time since i bought it, two years ago) and i notice there is a high pitch whine coming from the engine compartment when the AC is on. The noise isnt constant, and i usually notice it when im idling. What could it be? Maybe a belt or something?

The belt turns all the time. It would squeal. That can be tightened or replaced. So is it a SQUEAL or a WHINE. If it is a whine, it is probably the AC compressor.

Get a mechanics stethoscope. They can be extremely valuable in isolating rogue noises. Gotta be extremely careful though poking around.......If this noise ONLY occurs when the AC is on, then the AC compressor is definitely suspect, but a glazed or worn belt can fool you sometimes and only whine when under the larger load of the air conditioning. Replace the belt if it's old or shows evidence of glazing (shiny streaks). Goodyear Gatorback is my favorite belt.

Muffler Bearing.

Hallo. What about the famous Idler Pulley?
Spray water on the belt and listen. If the sound has gone, it's mostly the belt.:roflmao:

'92 XJ