Determining if you have a loose belt, a bad bearing, or a failing harmonic balancer can be difficult, but if you check a few things it can be much easier.My squeal occured when I used the powersteering, AC, or started the car. This means it isn't the water pump, or a compressor bearing. if the squealing only occured when the car started it would be more likely a water pump bearing. If it only occurs when you enage the AC then it is a compressor issue. A harmonic balancer reduces vibration by allowing some slipage between the belts and the engine. It also absorbs woble.I am opting to get my issue fixed by a professional because I don't have time, but replacing a harmonic balancer takes about 90 minutes and requires you use a puller tool, and know how to retension the belts.
Step 1: Listen
First, listen to the car to hear the type of noise and try to find the source.
Step 2: Identify the Issue
For this problem, it due to the different vibrations of the two rings separated by the rubber. A crack causes the vibration to create a loud noise. This location of the problem is awkward and difficult to fix, so the best option is to have a pro fix it.