Hello, it's a 2001 4 liter I6 and it's got this extremely loud, annoying squeal/screech when the car is turned on and the AC is on as well. HOWEVER, if the car is warm and I've been driving for a minute with the AC off, and I turn it on, no squeal. The noise gets louder with higher RPMs, and it's gotten so bad that I cannot turn the AC on until I've driven around for a bit and the belt has warmed up. With the AC off, it makes no squeals at all.

Loose belt, right? I thought so too. I replaced the belt with a new one, and it's tight on there, but it still makes the noise. That's why I think this is an issue with the compressor being low on oil or the clutch plates being worn out and sliding past each other (???).

I've never had any other issues with the AC and it's never leaked and it's always made the air cold.

A few other things to note is that when the AC clutch does click on/off, it's very audible in the cab, and the engine DOES have a distinctly different sound when revving up when the AC is on versus when it's off... it's like a separate little whirring noise, a tone much like what the engine itself makes, but an octave higher... it's hard to describe.

Any ideas would be super helpful. I don't want to waste money taking it in to the shop if I can fix it myself. Is it a bad clutch/worn clutch plates? Can I disassemble this and replace them? Or is it something else? Thank you.

 

Try a Goodyear Gatorback Belt. The cheaper ones squeel.

 

x2. Goodyear gator back is the best belt I have ever put on a 4.0

 

The fact that it goes away when the engine warms really points to the belt. If the AC clutch was bad it would most likely be consistent anytime you used the AC. A lot of people have trouble with off brand belts. The gator back gets good reviews and most folks love them. You can get a mechanics stethoscope cheap, allows you to listen to the AC compressor and see if you hear it grinding or squealing. Most auto parts stores have them.

 

And rock auto has good prices on them.