Poker Sarge

Hello Mustangs!

My 2008 Mustang V6 started to squeal when it was at idle or when I accelerated. I replaced the Serpetine belt, and then it only squealed when I accelerated. So I replaced the Auto-Belt Tensioner. That made the squealing very light, so I replaced the Idler Pulley. It now only squeals when the AC is on, and I am accelerating. It DOES NOT squeal when idle and AC is on, and DOES NOT squeal when AC is off and I accelerate.

it is actually went from a squeal to a chirp Chirp.

Please help...

dragon6813

i had that problem with my jeep ended up being the clutch for the ac does it squel if you rev the motor

dragon6813

and when it squels does the coolong power of the ac seem to drop at all

scottybaccus

It's probably the a/c compressor failing. As internal drag increases, the belt slips more. It's not the clutch, as indicated by going quiet when you turn off the a/c.

If it is squealing without the a/c on, it's likely the belt is glazing from the times it does slip. You should also check the tensioner to make sure it hasn't grown tired.

Poker Sarge

It doesn't squeal at all when the AC is off. It literally starts to squeal once I turn it on and stops squealing after a few seconds once I turn it off.

scottybaccus

That means your compressor is failing and starting to drag. It's days are numbered.

Chromeshadow

I had that problem with a Chevy, the crank pulley was worn smooth and it slipped with the added load of the AC. I was able to rough it up a little with emery cloth that killed the squeal.
I have also had an AC pump lock up, and there is not much you can do except replace the AC...this happened 100 miles from home and cost about $800 for a shop to replace it. If the AC pump fails you may not be able to drive the car.

MustyRen

My Mustang Squeals like a big in hell when ever i turn on a/c (idle and Accelerating)...The soudnd does go away after driving for a couple minutes though.
I found a rebuilt a/c compressor on ebay for cheap...Hopefully that will do the trick

crazyassracer

Squealing sounds during acceleration is a common problem with Mustangs.

Nuke

As much as I hate belt dressings, they DO help determining which accessory or accessory pulley is the culprit. Often, a misaligned pulley will cause a squeal or chirp.