I have a 2005 cummins 118k miles manual. The truck makes a chirp noise when I start it up. I spray some water on the Serpentine belt and then it goes away. Sometimes when I'm driving the truck it makes a squealing noise and sometimes gets worse with RPMs. Also, sometimes i hear this squeal while I'm driving then it goes away it is temperamental, sometimes it sounds terrible other times you can't hear a thing. All of my pulleys are tight, the water pump is not leaking anything,the belt is a little rough. Could it just be the belt since the chirp goes away with water but comes back when dried out? But, that doesn't explain the annoying squeal when driving sometimes?? Bad tensioner pulley?? any input will help. Thanks for your time.

 

turn your a/c on and off

 

Okay, when it is squealing really bad or when it is just chirping? where will this get me?

 

could be your ac compressor going it runs when your def is on too

 

Actually that makes sense because when i run my heat i always run it through the defroster, and thats when i heard it the worst last is when my defroster was on

 

disconnect the wires from the pump so it free wheels on def instead of running

 

sure will. could it be the idler pulley if its not the A/c?

 

possibly thats a cheap fix but i havnt had one go i have had the ac pump go. you can take the belt off and spin it see if it sound like a bowl of gravel