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Noisy A/c Compressor

zedbear

By zedbear
in Ask A GM Technician

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zedbear Enthusiast

zedbear

Posted
Posted

Just wondering what the typical causes of a noisy compressor are. It's making a "rrrrrrrrrrr" noise when accelerating. Increases in intensity with RPM. It is most noticable when the heat load is high, like on a muggy day. Don't really hear it at all when it's below 75 and dry out. A/C blows ICE cold otherwise. Thanks.

splat10 Enthusiast

splat10

Posted
Posted

probably a bead bearing on the pulley, or maybe a bad belt. Mine chirps like belt squeal and is super annoying but apparently not enough for me to to get around to changing the belt :thumbs:

zedbear Enthusiast

zedbear

Posted
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probably a bead bearing on the pulley, or maybe a bad belt. Mine chirps like belt squeal and is super annoying but apparently not enough for me to to get around to changing the belt :thumbs:

 

Bad belt, no. Bad bearing, I doubt it. I'm pretty sure the sound is coming from the compressor itself. Its making a sound sorta like a souped up engine with timing gears, lol. Kinda hard to describe this.

jro909 Senior Enthusiast

jro909

Posted
Posted

sound like a metallic swirling sound? because mine sure enjoys making that noise...idk if it increases with rpms, the engine and the radio tend to cover up most noises

zedbear Enthusiast

zedbear

Posted
  • Author
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sound like a metallic swirling sound? because mine sure enjoys making that noise...idk if it increases with rpms, the engine and the radio tend to cover up most noises

 

Maybe.

 

Next warm day we get, I'll hook up my gauges and see whats up. Wondering if the shady dealer I bought it from "topped off" the refrigerant before selling it, possibly over-charging it.

 

Or it may just need a little oil.

rogersinsel Enthusiast

rogersinsel

Posted
Posted

My Impala is noisy, it always has been. My Tahoe is very quiet.

 

Th

Just wondering what the typical causes of a noisy compressor are. It's making a "rrrrrrrrrrr" noise when accelerating. Increases in intensity with RPM. It is most noticable when the heat load is high, like on a muggy day. Don't really hear it at all when it's below 75 and dry out. A/C blows ICE cold otherwise. Thanks.
  • 1 month later...
zedbear Enthusiast

zedbear

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Posted

Finally hooked the gauges up. Ambient temp around 80 degrees. Low humidity.

 

Static pressure was 65/65

 

At idle, max a/c, doors open: 43/225, vent outlet temp 48F.

 

1500 rpm, max a/c, doors open: 33/200, vent outlet temp 38F............

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

Everything looks good there.

 

I had a compressor get noisy on my '94 K1500 when the low pressure cut off switch took a crap on me. I didn't notice it right away because I always had the radio cranked. The comp wasn't cycling, which caused the oil to slug ... and basically smoked the compressor. Got REAL noisy after that.

zedbear Enthusiast

zedbear

Posted
  • Author
Posted
Everything looks good there.

 

I had a compressor get noisy on my '94 K1500 when the low pressure cut off switch took a crap on me. I didn't notice it right away because I always had the radio cranked. The comp wasn't cycling, which caused the oil to slug ... and basically smoked the compressor. Got REAL noisy after that.

 

Mine appears to be cycling normally. Could the system need a little oil? Or maybe it's just worn out?? Its sort of embarrasing to drive, lol.

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

If it were me, with 38° vent temps I'd leave well enough alone. I wouldn't go adding oil to a system without knowing exactly how much is in there. Too much oil will smoke a compressor almost as fast as not enough oil. The only way to know exactly how much is to recover the charge & measure the oil. If you don't have a machine, you'd have to flush each component & start from scratch - not something I'd be willing to do when it's working perfectly fine.

zedbear Enthusiast

zedbear

Posted
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If it were me, with 38° vent temps I'd leave well enough alone. I wouldn't go adding oil to a system without knowing exactly how much is in there. Too much oil will smoke a compressor almost as fast as not enough oil. The only way to know exactly how much is to recover the charge & measure the oil. If you don't have a machine, you'd have to flush each component & start from scratch - not something I'd be willing to do when it's working perfectly fine.

 

Can you shed any light on possible causes of this noise? I wish I could record it but I don't think it would get picked up very well. I may just take it in to a shop to have it looked at. My primary concern is whether the noise means compressor failure at some point. Is "black death" a concern with these systems? I'd hate to just leave it and have that happen. Then I have to replace everything lol.

 

Thanks for the info.

  • 2 months later...
jjwangen New Member

jjwangen

Posted
Posted

hey guys, just signed on to try to figure out a problem i am having with a 2000 2500 6.0L. the guys original compressor made a lot of noise for a long time until it quit working. he brought it to me and said he wanted it all replaced with new stuff. i took out his orifice tube and saw it was covered in metal shavings, so i put in a new condenser, new dryer, new orifice tube, and reman (4seasons) compressor. i did flush the system with fjc ac flush and compressed air first. then i put in 8 oz of pag150 oil and charged with fresh 134a. the system works great, blows cold, but makes a lot of noise. sounds like the noise that this post is about. not a terrible sound, just loud. i have checked belt, tensioner, mounting bracket, cant find it. today i got another reman compressor from my parts store (and new dryer and o tube to comply with warranty requirements) and installed the new parts. i put 2 oz of oil directly into the compressor and spun it by hand several times before installing it. i vac'ed the system for 30 minutes and charged it again and...............just as loud as the last one!!!!!!!!!! i dont know what to do, i may have to eat the first compressor i got for it and i have waaaay too many hours into a project i didnt make much on in the first place. anyone have an idea?

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