Truck running switch on the A/C it starts squealing really loud?

Tiny
BOBBYBOY76
  • MEMBER
  • 2009 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 2WD
  • 160,000 MILES
I really need some help with this. When my truck is running and I switch on the a/c it starts squealing really loud. Like I think the compressor clutch stops or maybe is hesitating. I've already changed out the compressor, tensioner pulley, and belts but it still hasn't fixed the issue. Does someone have any other ideas?
Sunday, August 25th, 2024 AT 6:59 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,052 POSTS
Hi,

If it only happens when you turn on the AC, the compressor sounds like it is locked up. You indicated the installation of a new compressor. If you disconnect the power lead to the compressor, does it still make the noise?

Also, if everything is new, there could be an issue with too much PAG oil, or it could be overcharged. Let me know what and how things were done to recharge the system after the replacement compressor was installed.

Take care,

Joe
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Sunday, August 25th, 2024 AT 8:07 PM
Tiny
BOBBYBOY76
  • MEMBER
  • 4 POSTS
On a cold start it will squeal for a couple seconds and then quit but other than that it only does it when A/C is on. After the compressor installed, which I bought brand new, it was vacuumed and then charged with the amount of refrigerant specified. It was reading good on the gauges. It was supposed to have some compressor oil in the compressor when I bought it but when I tried draining it only a couple drops came out. So, I then put 4 oz of compressor oil in the compressor, installed it, and after the refrigerant charge I put three more oz of oil. And to answer your question, no it doesn't squeal with the compressor unplugged.
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Monday, August 26th, 2024 AT 6:16 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,052 POSTS
Hi,

I have a feeling there is too much PAG oil in it. The entire system only holds 7.1 ounces. You added 7 ounces to what was still in the system.

If the refrigerant is properly charged, either there is too much oil, or the new compressor is locking up.

Joe
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Monday, August 26th, 2024 AT 8:10 PM
Tiny
BOBBYBOY76
  • MEMBER
  • 4 POSTS
I will check and let you know what I find out.
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Monday, August 26th, 2024 AT 11:14 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 49,912 POSTS
This takes a special belt, it's like a rubber band, you must get the right one or it will squeak. Here are the instructions. Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.
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Tuesday, August 27th, 2024 AT 9:39 AM
Tiny
BOBBYBOY76
  • MEMBER
  • 4 POSTS
Hey guys, I just wanted y'all to know I found the problem. Turns out the wires to my crank sensor were bare and touching. I'm not sure what that has to do with my A/C but after I separated them the a/c started working fine. Thanks for all the input.
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Sunday, September 1st, 2024 AT 8:07 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 49,912 POSTS
Glad you could get it fixed, thanks for letting us know. Please use 2CarPros anytime we are here to help.
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Sunday, September 1st, 2024 AT 10:51 AM

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