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Groaning noise, serpentine belt wobbling with A/C on


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sancho
User

Dec 20, 2019, 11:18 PM

Post #1 of 5 (427 views)
Groaning noise, serpentine belt wobbling with A/C on Sign In

Whenever my a/c is running, there is a groaning/ whirring noise that only really occurs around 1200 to 1500rpm. The sound seems to come and go, seems to be worse on hot days.

At first I thought it was the a/c compressor itself making the noise but I had that checked out and it was given a clean bill of health.

I’ve since noticed that it is the serpentine belt itself that is wobbling excessively but only in that rpm range. And it seems to be the belt that is making this noise as it resonates.

Any ideas? Thanks in advance.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 21, 2019, 10:22 AM

Post #2 of 5 (394 views)
Re: Groaning noise, serpentine belt wobbling with A/C on Sign In

? The key point you used is "only when A/C is on" that it does this. Year, make and model would help but this is more generic than that I think.


Most would wobble or make noise when OFF there's a bearing inside the clutch to compressor works when off is static when engaged. Compress passed a "good bill of health means it's still working as it should most likely" so the noise and wobble overlooked by chance?


Thing to do is take the belt off I'm not convince the clutch isn't at fault yet. Then spin any and all pulleys, torque on them for the wobble there should be none.


Would be rare but the belt itself may be screwed up, not installed properly and somehow stays on the thing or oddly stretched or mis-made somehow.


That above should find what the real fault is.


FYI if shaft of a compressor is in fact making noise you wont feel that by hand rather listening rod with it operating is a horrible sign to tend that ASAP before it self destructs - OK?


T



sancho
User

Dec 21, 2019, 11:13 AM

Post #3 of 5 (387 views)
Re: Groaning noise, serpentine belt wobbling with A/C on Sign In

It’s a 2013 Hyundai Elantra.

That’s sort of part of the problem. The noise/ wobble seems to come and go. The mechanic wondered if it was related to the gas pressure being too high and regassed the compressor. The day after getting the car back there was no noise at all, then by the next day it was back with a vengeance. I dare say it does seems to be worse on really hot days.

I had assumed that the fact that it wasn’t consistent meant that it wasn’t the pulley. But I could be completely wrong.

When you say there’s a bearing inside the clutch that works when off, do you mean if the bearing was failing, the wobble would occur with the a/c off?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 21, 2019, 12:04 PM

Post #4 of 5 (381 views)
Re: Groaning noise, serpentine belt wobbling with A/C on Sign In

Hmmm, clue lurking about "regassing" as you put it made this go away for a day? Is A/C needed and working where you use this car now? That matters of course.
It's critical that in "regassing" almost anything that you remove what is/was in a system and put back exactly the correct amount no guessing those days long gone or you have the wrong help.


If A/C is needed does it work and stay at expected output to inside car? In one day if the system lost "refrigerant" and that was a reason for noise it also should work well or maybe not at all?


Too much "gas" as you put it would choke and yes could make noise over that up to damage plus also not work properly so it's all easier if I/you know it works.


About compressor with clutches: The clutch is just a blank pulley when compressor is OFF or disengaged the whole body of compressor is just a bracket to hold it there as a pulley. When engaged/compressing center spins at same RPM as the belt so that bearing is dead weight then yet turning the shaft of compressor is then the acting bearing(s) bushings.


If you personally see this belt wobble is it up and down or side to side should find that with it OFF vehicle and moving the pulleys belt rides on - all of them but if only with A/C use point to that one or a maybe an idler/tensioner one because it's then under a load working harder.


Who is going to fix this, you or only a mechanic? If the one mentioned isn't finding this I'm not sure why it isn't new or wild high tech with an obvious belt wobble to anything.


It matters who's doing what you shouldn't need to ask if it's all theirs to figure out but is up to you to give them the best description of the problem you notice and the time to find an fix it.


If you alone can remove a belt (engine off checking) pulleys go ahead.


One thing is for sure - it really can't stay this way sooner or later something is going to break and make itself clear what is was I hope you can avoid that ASAP as already said,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 22, 2019, 10:05 AM

Post #5 of 5 (353 views)
Re: Groaning noise, serpentine belt wobbling with A/C on Sign In


Quote
At first I thought it was the a/c compressor itself making the noise but I had that checked out and it was given a clean bill of health.


How can a tech determine it is not compressor but not know what it actually is?

That's about the only way to eliminate the compressor is to determine what actually is making the noise.



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