Help with serp. belt chirp/squeal

[Whozyodaddy]

Need help with recent chirp/squeal from serpentine belt on my ‘16 GT. I have searched some of the other posts, but I’m still a bit lost on what to do.

When A/C is on and I’m driving around, I get the occasional belt chirp/squeal and it seems to be getting worse and more frequent. I popped the hood today and ran the car with A/C on for a bit but couldn’t get the noise (only does it with A/C on). Anyway, I noticed some wear on the outside of the serp. belt (just half of it closest to the motor) and some black spatter on the front of the motor. The spatter looked rubbery, but dry. I’m not sure what it is (maybe a belt dressing someone sprayed on it?) I’ve not owned the car very long and it only has 26k miles.

All of the pulleys seem in good shape and I watched the A/C clutch kick on and off with no noise or issue.

Any thoughts?? Where to start?

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[atomicpunk]

The chirp/squeal is the belt slipping, the black spatter is the belt getting hot and melting. I would take the belt off and spin the pulleys and by hand and feel and listen for roughness/noise. Since it does it with the AC on I would start with AC compressor. That belt is going to need replacing too.

 

[Cobra Jet]

The most common failure of the FEAD system on the S550 5.0 is the A/C field coil/clutch head which also contains the pulley. My guess is that your A/C clutch is on its way out.

This thread has the info from the Ford shop manual for how to replace it:
https://www.mustang6g.com/forums/th...tentially-a-c-compressor.129712/#post-2686995

This thread was from another M6G Member who had a similar issue as yours and it did turn out to be the A/C field coil/clutch head:
https://www.mustang6g.com/forums/threads/what-is-this-passenger-side-lower-main-pulley-ac.121072/

There is also the DIY of an additional belt tensioner to the Coyote which some say helps with the A/C issues:
https://www.mustang6g.com/forums/threads/uh-guys.113536/

 

[Ock]

The chirp/squeal is the belt slipping, the black spatter is the belt getting hot and melting. I would take the belt off and spin the pulleys and by hand and feel and listen for roughness/noise. Since it does it with the AC on I would start with AC compressor. That belt is going to need replacing too.

Off topic... but is your profile pic from Better off dead?

 

[atomicpunk]

Off topic... but is your profile pic from Better off dead?

yes, lol

 

[Ock]

yes, lol

haha i knew it... one of my fav movies... how did u not get a camero? lol

 

[Whozyodaddy]

Thanks!!

 

[Whozyodaddy]

So to renew this question for further help….the ac clutch seems to be working correctly and the wear that I am seeing is only on the exterior of the serpentine belt. Could another pulley or tensioner in the serpentine system be causing the wear on the outside of the serp belt and the chirp when ac is on? Or could it be the ac clutch that is causing some issue with the serpentine system and the wear on that belt??

 

[Whozyodaddy]

…and today I ran the heater without the AC on and the belt system still chirped/squealed. I believe this is telling me that it is likely not the AC clutch causing the issue, but the tensioner and/or idler pulley. Does this sound right??

 

[Ponyupnow]

Check and see if your ac is not seizing, also check all your pulleys and the tensioner, something similar happened to me on my dodge diesel and the tensioner pulley was the culprit. Seems your serpentine belt might be rubbing on a speed sensor or is not sitting in its correct place. Also the chirp tends to happen under load in most cars so just having it idle may not be enough to diagnose.

 

[Whozyodaddy]

From a basic visual, I can’t see anything misaligned. The AC clutch seems to operate normally, but I can only see this at idle. How can I tell if it is seizing?

Also, the chirp is under moderate load on acceleration and deceleration, but nothing consistent

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