Beginnng of problem: When the AC started there was a slight squealch/squeal sound lasting for 1/2 second.
Now: Same at start-up but seems to be slightly louder and also occurs when vechile is in motion. Occuring every 30 seconds or so for about 4-5 minutes. Long term problem or something just needing adjustment?
AC still functioning normally except for the above.
Refer to the picture attached. One of two problems: either the tensioner pulley is loose or the belt needs to be replaced. You can use this image to help you fix either problem. Locate the place on the real belt where the #2 is located in the image. Push or pull on the belt. If you can move it more than an inch or so, without moving the tensioner, replace the belt. You shouldn't use much more than about 20 or 30 pounds of force. Another test is to twist the belt in the middle of its longest between pulleys run.