Subaru Repair: squeal under hood, high pitch, subaru legacy

Question
I have a '93 Subaru Legacy that just started to put out a high pitch chirp when I accelerate. The high pitch chirp only lasts about 5 seconds and goes away. If I keep the car at a steady rate of speed, the chirping diminishes. There is a gray discoloration on the outside of the belt toward the inside of the belt but the inside looks good, no cracks.

Answer
Sounds like a possible ac compressor problem or as simple as a loose or worn ac belt.Whenever the defrost or ac is selected with the mode selector on the dash the ac compressor will cycle on for a brief period of time.If the belt is loose or the compressor has a issue it will make noise.Hope that helps