noise from belt on 2003 Chevrolet Tahoe

I get a noise from the belt off the air compressor. Just changed the compressor the pulley and the belt and still get the same squeeking noise. Once I give the truck gas or drive off with the air conditioning on it makes that noise without the air no noise. What can i do to fix it?

Asked by for the 2003 Chevrolet Tahoe
It crucial that the pulleys are all lined up correctly. GM even has a tool with a laser pointer on it to determine the correct alignment.
Can you determine where the noise is coming from? I normally use a stethoscope, or a long screwdriver to locate the source of the noise, but this approach is very dangerous, so if your not experienced with this method I wouldn't try it.
2 more answers
if alignment and tension is found ok, check the a/c pressures. too high an a/c pressure will make it harder to turn the compressor and may be caused by overcharged when replaced, too much oil or lack of condensor cooling which may have caused the original one to fail.
compressor is suffering from "slagging". this happens because the compressor is poistioned low and struggles for oil. if your model has the new system to correct this problem then most likely your compressor is going out and will need to be replaced. this is much cheaper than trying to fix the slagging problem.