God-awful A/C squeal

[Hippo393]

Hi Gang,
Upon A/C actuation, I had been getting an awful squeal for months...until it eventually tore up my belt. Today before putting a new belt on, I did have to clean up heavily melted belt material on the AC pulley. All cleaned up and tightened, I still get the same LOUD squeal the moment I press the A/C button. However, both the AC and tensioner pulleys turned freely when tested before belt replacement today.

I don't get it. Compressor (from NAPA) is less than 2 years old. Could it be that?

For what it's worth, I have done my own AC work for years and never had this odd issue. Some threads I've read said to use WD-40, others have said to use belt dressing, others said NOT to use belt dressing. Gah!
Your thoughts?

-Alan :laser:

 

[pauldub]

Do you have enough tension on the belt to keep it from squeeling?

 

[TheDurk]

Did you try turning the compressor while the clutch was engaged, or only when the system was off? 'Cuz it does sound like a seized compressor.

 

[nissanh]

Squeal and especially the melted belt probably due to a bad bearing. I bet it is the bearing in the AC compressor. Any aftermarket compressor uses Chinese low quality bearing and those wear out in less than 3000 miles.

I even replaced my car's AC compressor bearing with a Chinese bearing in about a year ago, and now at 9000 miles the bearing is shot.

Is the AC pulley or idler spins many rounds before coming to a stop? this is a sign of a bad bearing.

 

[Hippo393]

Do you have enough tension on the belt to keep it from squeeling?

Yes. Once I thought it was too tight, so I loosened it and still squeals. Back to regular tightness = God Awful squeal.

 

[Hippo393]

Did you try turning the compressor while the clutch was engaged, or only when the system was off? 'Cuz it does sound like a seized compressor.

TheDurk: good question, not sure how to turn the compressor while the clutch is engaged.? Would that be with the belt off, engine running, and push in the A/C button, then turn compressor while the motor's whizzing? Can that be done safely?

I think you're right...the pulley seemed fine as I was putting on the belt, but that's without the clutch engaged. Once engaged, it most likely siezed, thus melting the belt and depositing said melted belt on one spot on the pulley.

Factory replacement then? :brick:

Thanks,
-Alan

 

[RonJR]

Don't get your hands in there with the engine running, AC belt or not. Too many other things to grab you and maim you.

The clutch just needs 12V to be engaged; the engine doesn't have to be running. Just remove the belt, turn on the ignition, engine off, and turn on AC, and it should click in. Then you'll be able to tell if the compressor will turn freely or not.

Very likely though, that the compressor is seized. Time to get it out of there.

 

[TheDurk]

^^^^^^^What he said.....Belt off, Motor off, key on, A/C on, should engage clutch, if R-134a is at charge.

TheDurk: good question, not sure how to turn the compressor while the clutch is engaged.? Would that be with the belt off, engine running, and push in the A/C button, then turn compressor while the motor's whizzing? Can that be done safely?

I think you're right...the pulley seemed fine as I was putting on the belt, but that's without the clutch engaged. Once engaged, it most likely siezed, thus melting the belt and depositing said melted belt on one spot on the pulley.

Factory replacement then? :brick:

Thanks,
-Alan

You'll need a complete systemflush, and maybe new expansion valve as well as receiver/dryer. Seized compressor tends to grenade small pieces of crap throughout the system and they need to get cleaned out.

Definitely get a new Denso, but does not need to be from Toyota.

 

[19963.4lsr5]

I bought my flush kit from a place in Florida. It was called "Polar xxxxx" got my service tools for clutches and compressor repair there too. If you never seen how a AC compressor works internally it's pretty neat.


Sent from my iPhone using Tapatalk

 

[Hippo393]

Service Port?

Please advise on this one piece: after driving for 5 - 10 minutes, then pressing the A/C button, the compressor squeals for about 1 -2 seconds, and then everything quiets down and works fine...cools the cabin for as long as I am on the road. How does that happen that it's "seized" at startup but not after a few minutes of driving? What could that symptom be indicative of?

Oh, and what use is the "service valve" on the compressor? What's serviced via it? And could possibly utilizing the service valve with oil, or whatever, help alleviate the initial startup seize issue? Not sure of its purpose. Please advise.

Thanks gang!! :hatsoff:

 

[sawguy]

Please advise on this one piece: after driving for 5 - 10 minutes, then pressing the A/C button, the compressor squeals for about 1 -2 seconds, and then everything quiets down and works fine...cools the cabin for as long as I am on the road. How does that happen that it's "seized" at startup but not after a few minutes of driving? What could that symptom be indicative of?

Oh, and what use is the "service valve" on the compressor? What's serviced via it? And could possibly utilizing the service valve with oil, or whatever, help alleviate the initial startup seize issue? Not sure of its purpose. Please advise.

Thanks gang!! :hatsoff:

Mine does the exact same thing since I replaced all the belts. They are all tight.

 

[catrains]

Please advise on this one piece: after driving for 5 - 10 minutes, then pressing the A/C button, the compressor squeals for about 1 -2 seconds, and then everything quiets down and works fine...cools the cabin for as long as I am on the road. How does that happen that it's "seized" at startup but not after a few minutes of driving? What could that symptom be indicative of?

Oh, and what use is the "service valve" on the compressor? What's serviced via it? And could possibly utilizing the service valve with oil, or whatever, help alleviate the initial startup seize issue? Not sure of its purpose. Please advise.

Thanks gang!! :hatsoff:

my guess is you have too much refrigerant in the system. when this happens the compressor valves get liquid refrigerant in the compressor so when you turn ac on the clutch engages compressor and the liguid does not compress so it locks up or resists movement.

ONLY REFRIGERANT GASES ARE ALLOWED IN THE COMPRESSOR.
there are some that install after market components that protect from this effect where some times it can happen under certain conditions.

the ac compressor should be mounted higher than the rest of the system . this was done decades ago . now with these mounted down low below all the ac components it can get liquid in the compressor esp. if its over filled !

with the ac off and you run the engine for 15-20 min the ac compressor will heat up this will vaporize the liquid from the compressor so then it runs . on a cold start liquid is puddling up in the compressor not good.. compressor valves/belt etc will get f'ed up quickly..

 

[Hippo393]

my guess is you have too much refrigerant in the system. when this happens the compressor valves get liquid refrigerant in the compressor so when you turn ac on the clutch engages compressor and the liguid does not compress so it locks up or resists movement.

ONLY REFRIGERANT GASES ARE ALLOWED IN THE COMPRESSOR.
there are some that install after market components that protect from this effect where some times it can happen under certain conditions.

the ac compressor should be mounted higher than the rest of the system . this was done decades ago . now with these mounted down low below all the ac components it can get liquid in the compressor esp. if its over filled !

with the ac off and you run the engine for 15-20 min the ac compressor will heat up this will vaporize the liquid from the compressor so then it runs . on a cold start liquid is puddling up in the compressor not good.. compressor valves/belt etc will get f'ed up quickly..

Good info! So if that's true, then does it stand to reason that by removing some of the refrigerant, the symptom should go away?

 

[catrains]

Good info! So if that's true, then does it stand to reason that by removing some of the refrigerant, the symptom should go away?

I would place a gauge set on the system and monitor the pressures. increase RPM to about 1000-1200 RPM. see what the pressures are with fan on max and the doors all open @80 deg F air temp..

low pressures should be 40-45 PSI. the high pressures 225-250 PSI,,.

being in this range at those air temps should be about right.

another way to find if too much refrigerant is in system is the high pressures will rise to high levels quickly when adding refrigerant. so If you see like 325psi and higher then too much is in there....@80deg F air temps.

post what the high side pressures are @80 F.. should not be in the 300PSI + range ........

 

[Hippo393]

I would place a gauge set on the system and monitor the pressures. increase RPM to about 1000-1200 RPM. see what the pressures are with fan on max and the doors all open @80 deg F air temp..

low pressures should be 40-45 PSI. the high pressures 225-250 PSI,,.

being in this range at those air temps should be about right.

another way to find if too much refrigerant is in system is the high pressures will rise to high levels quickly when adding refrigerant. so If you see like 325psi and higher then too much is in there....@80deg F air temps.

post what the high side pressures are @80 F.. should not be in the 300PSI + range ........

Will do. Temps now are cool, but soon will be 80*+ here in NC. Might not get to this for a week or two due to family oblig's. Stay tuned. Thanks!!! :clap2:
-Alan

 

[SaulG]

Also compressor clutch air gap..may be dirty/oil soaked/to large...

 

[Hippo393]

I would place a gauge set on the system and monitor the pressures. increase RPM to about 1000-1200 RPM. see what the pressures are with fan on max and the doors all open @80 deg F air temp..

low pressures should be 40-45 PSI. the high pressures 225-250 PSI,,.

being in this range at those air temps should be about right.

another way to find if too much refrigerant is in system is the high pressures will rise to high levels quickly when adding refrigerant. so If you see like 325psi and higher then too much is in there....@80deg F air temps.

post what the high side pressures are @80 F.. should not be in the 300PSI + range ........

Just got to this today, outside temps were around 80*F: Hi pressure at idle was 175, low 34. at 1000-1200 rpms, the high went down to about 155, low to about 22.

What does this tell you? Is it actually underfilled? The A/C blows an epic 39*F when driving, but it takes a good 15-20 minutes of driving in the hot-a$$ heat before I can attempt to turn the A/C on without that god-awful squeal.

Thanks!
-Alan

 

[catrains]

Just got to this today, outside temps were around 80*F: Hi pressure at idle was 175, low 34. at 1000-1200 rpms, the high went down to about 155, low to about 22.

What does this tell you? Is it actually under filled? The A/C blows an epic 39*F when driving, but it takes a good 15-20 minutes of driving in the hot-a$$ heat before I can attempt to turn the A/C on without that god-awful squeal.

Thanks!
-Alan

well those pressures are a bit low. so I would say not over filled .

try this method before shutting down engine turn off ac for a couple of min .. then see if it squeals on the next cold start.

could be the ac system is low on oil or the compressor is failing.
I would next step add a couple of OZ of oil to the system. make sure you use the correct oil and viscosity. see if that helps. older systems do over time loose oil ..

 

[mtbtim]

Just got to this today, outside temps were around 80*F: Hi pressure at idle was 175, low 34. at 1000-1200 rpms, the high went down to about 155, low to about 22.

What does this tell you? Is it actually underfilled? The A/C blows an epic 39*F when driving, but it takes a good 15-20 minutes of driving in the hot-a$$ heat before I can attempt to turn the A/C on without that god-awful squeal.

Thanks!
-Alan

I know you've said you've done your own AC work for a long time but if your pulleys move freely and feel smooth, it sure sounds like the belt isn't tensioned correctly. A properly tightened belt should have 1/2"-3/4" of deflection. If you have a tension gauge, that's even better.

Here's a video [MENTION=102606]infamousRNR[/MENTION] and I made for replacing the belts and properly tensioning them.

<iframe width="560" height="315" src="https://www.youtube.com/embed/Zi1XfFUOjKc" frameborder="0" allowfullscreen></iframe>

 

[LittleCaesar]

Sounds undercharged to me. High side is usually 2x the outside temp +50 give or take a few psi numbers.

The squeal, if not the belt, can be the bearing going south.

How is static pressure?