2016 Peterbilt 389 with 12.7 liter Detroit 60 Series. New alternator. New pulley. New tensioner. New belt. Cranked the truck up. No problem. Turned the AC on and it started squealing like a pig. Turned AC off and it went back to normal. The AC was working just fine before. Put in 2 new pressure switches. Checked freon level. Clutch is working. Pulley spins freely when we spun it without the belt. Any help would be greatly appreciated. The water pump is also running on the same belt.
crank the truck up and let it idle.
lightly spray the belt only, with soapy water from a spray bottle while idling. That or rub dry-soap from a bar of soap ... If the squealing stops as the belt gets soap on it, then it is the belt squeeling and not a pulley.
Here is some related info on squealing belts, so that I don't have to repeat myself ...
ref:
http://rawze.com/forums/showthread.php?t...6#pid76836
Just went through this with my Tripac, took a wire wheel to all the pulleys on the same belt. No more squeal..