Strange AC problem? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ApacheIvan · 07-12-2017, 02:23 AM

Is my alternator bad? When I turn on my AC my alternator sounds like it is going out. sounds like the bearings in the alternator starts squealing, it is fairly new, the belt is tight, turn the AC off and all is great. I thought it was a belt at first, but it is coming from the alternator for sure.. anyone else have that happen?

**truckster** · 07-12-2017, 09:49 AM

AC does increase the electrical load. That's the only connection I can think of.

Andy4639 · 07-12-2017, 10:00 AM

How do you have the belts routed? Is this the old v-belts are serpintine belt.
The compressor electrical out put will not make the alternator bearing go out and if it runs ok with the ac off then its in the compressor side.
I would find it hard to be the alternator on what you have posted.

The only thing I can think is one of the components isn't lined up good and putting stress on the alternator pulley.

ApacheIvan · 07-12-2017, 11:24 AM

Quote:

Originally Posted by Andy4639

How do you have the belts routed? Is this the old v-belts are serpintine belt.
The compressor electrical out put will not make the alternator bearing go out and if it runs ok with the ac off then its in the compressor side.
I would find it hard to be the alternator on what you have posted.

The only thing I can think is one of the components isn't lined up good and putting stress on the alternator pulley.

It is the stock configuration, stock type belts. I will do a bit more investigation today with a stethoscope and see if I can pin it down. All the alignment looks fine. It sure sounds like the alternator side.

ApacheIvan · 07-12-2017, 11:57 AM

Ok, so I guess I should not assume I am having the same issue twice. Just popped the hood and turned on the AC at idle and I can see the clutch hesitating at times, meaning it looks like I have a strobe light on it.. it is either failing or needs freon or oil.. I am not really savvy on the internal working of an A6 compressor, I don't want to throw away money trying to figure out if I need to replace the compressor, they are expensive enough.

Suggestions?

**Stocker** · 07-12-2017, 12:17 PM

Quote:

Originally Posted by ApacheIvan

..... turned on the AC at idle and I can see the clutch hesitating at times, meaning it looks like I have a strobe light on it.. it is either failing or needs freon or oil..

Subscribed... my new compressor also occasionally cycles on-off-on rapidly, the shop said the system is full....??

**Stocker** · 07-12-2017, 10:34 AM

Mine is making sounds similar to what you describe, but my stethoscope says the noise is coming from the compressor.
My alternator, water pump, and PS pump all sound normal.
Just bought the compressor at NAPA.... and it was made in China.

**dmjlambert** · 07-12-2017, 11:32 PM

I learned the hard way that if you get a Duralast belt from Autozone or other house brand from auto parts stores, they are not adequate. They stretch and don't hold tight enough to the pully. You must get a Gates brand belt. When you get one you will immediately see the difference. Autozone probably has Gates, I know O'Reilly does.

ApacheIvan · 07-13-2017, 12:57 AM

Quote:

Originally Posted by dmjlambert

I learned the hard way that if you get a Duralast belt from Autozone or other house brand from auto parts stores, they are not adequate. They stretch and don't hold tight enough to the pully. You must get a Gates brand belt. When you get one you will immediately see the difference. Autozone probably has Gates, I know O'Reilly does.

That is what I am going to do in the morning. I think that is what it happening. I have the belt so tight it has stretched and actually gotten narrower.

**leddzepp** · 07-13-2017, 01:38 AM

Does the AC work? (When the belt isn't squealing anyways). How hot was it outside?

ApacheIvan · 07-13-2017, 01:49 AM

Quote:

Originally Posted by leddzepp

Does the AC work? (When the belt isn't squealing anyways). How hot was it outside?

Yes everything works, all brand new. I do have to take the POA back out and adjust the pressure for r134 but other than that yes..

And it is in the upper 90s

**jeffahart** · 07-13-2017, 12:38 PM

I am running a gates 7555 for the A/C and fan. It squealed a bit at first but after running it a bit I cinched it down again after it settled in . No more pig squeals.

ApacheIvan · 07-13-2017, 01:02 PM

Quote:

Originally Posted by jeffahart

I am running a gates 7555 for the A/C and fan. It squealed a bit at first but after running it a bit I cinched it down again after it settled in . No more pig squeals.

I just ordered my Gates 7555. Will get it tomorrow.. we will see

cleszkie · 07-13-2017, 04:26 PM

If all else fails, you can take some emory cloth to the pulley grooves to give them some "bite", and to remove any old burnished belt material. I do not recommend using any sort of "belt conditioner" or "belt dressing" to increase belt grip on the pulleys. That stuff just makes a mess, and can make the problem worse in some cases.

X2 on the Gates belts.

**dmjlambert** · 07-13-2017, 04:23 PM

What is your opinion of belt and hose dressing? I've seen cans and pouches of it at the store and wondered about it. Good? Bad? Waste of time and money or good stuff?

**Stocker** · 07-13-2017, 05:42 PM

Quote:

Originally Posted by dmjlambert

What is your opinion of belt and hose dressing?

Quote:

Originally Posted by cleszkie

I do not recommend using any sort of "belt conditioner" or "belt dressing" to increase belt grip on the pulleys. That stuff just makes a mess, and can make the problem worse in some cases.

I agree with cleszkie, I tried belt dressing a long time ago and it made a mess and fixed nothing. Never again.

I have used a bar of soap to chase a squealing belt, but then I adjust it or replace it as necessary. The belt, not the soap....

ApacheIvan · 07-17-2017, 06:36 PM

Gates 7555 came today, on the truck already, night and day! No more slipping, you can just tell that there is more weight and girth to the belt. Thanks for the recommendation!

**jeffahart** · 07-17-2017, 07:27 PM

I keep a 7355 power steering, 7525 Alternator and the 7555 AC belts hanging from my ceiling for spares. Along with the upper 20607 and the lower 20694 Rad hoses. Because.... that's the way we've always done it around here!

ApacheIvan · 07-21-2017, 11:23 PM

The Gates 7555 belt made all the difference in the world. No more stretching, no more squealing, looks and works great!

07-12-2017, 02:23 AM	#1
ApacheIvan Registered User Join Date: Nov 2011 Location: Dallas TX. Posts: 1,053	Strange AC problem? Is my alternator bad? When I turn on my AC my alternator sounds like it is going out. sounds like the bearings in the alternator starts squealing, it is fairly new, the belt is tight, turn the AC off and all is great. I thought it was a belt at first, but it is coming from the alternator for sure.. anyone else have that happen? __________________ Dale - ApacheIvan 1972 Chevy Custom/20 Custom Camper Highlander http://67-72chevytrucks.com/vboard/s...d.php?t=740479 Original Owner Do you have a 1972 Plaid Pickup?

07-12-2017, 09:49 AM	#2
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,869	Re: Strange AC problem? AC does increase the electrical load. That's the only connection I can think of. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

07-12-2017, 10:00 AM	#3
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Re: Strange AC problem? How do you have the belts routed? Is this the old v-belts are serpintine belt. The compressor electrical out put will not make the alternator bearing go out and if it runs ok with the ac off then its in the compressor side. I would find it hard to be the alternator on what you have posted. The only thing I can think is one of the components isn't lined up good and putting stress on the alternator pulley. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

07-12-2017, 11:57 AM	#5
ApacheIvan Registered User Join Date: Nov 2011 Location: Dallas TX. Posts: 1,053	Re: Strange AC problem? Ok, so I guess I should not assume I am having the same issue twice. Just popped the hood and turned on the AC at idle and I can see the clutch hesitating at times, meaning it looks like I have a strobe light on it.. it is either failing or needs freon or oil.. I am not really savvy on the internal working of an A6 compressor, I don't want to throw away money trying to figure out if I need to replace the compressor, they are expensive enough. Suggestions? __________________ Dale - ApacheIvan 1972 Chevy Custom/20 Custom Camper Highlander http://67-72chevytrucks.com/vboard/s...d.php?t=740479 Original Owner Do you have a 1972 Plaid Pickup?

07-12-2017, 10:34 AM	#7
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,577	Re: Strange AC problem? Mine is making sounds similar to what you describe, but my stethoscope says the noise is coming from the compressor. My alternator, water pump, and PS pump all sound normal. Just bought the compressor at NAPA.... and it was made in China. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

07-12-2017, 11:32 PM	#8
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,631	Re: Strange AC problem? I learned the hard way that if you get a Duralast belt from Autozone or other house brand from auto parts stores, they are not adequate. They stretch and don't hold tight enough to the pully. You must get a Gates brand belt. When you get one you will immediately see the difference. Autozone probably has Gates, I know O'Reilly does.

07-13-2017, 01:38 AM	#10
leddzepp Moderator Join Date: May 2007 Location: Southern Cal Posts: 19,995	Re: Strange AC problem? Does the AC work? (When the belt isn't squealing anyways). How hot was it outside? __________________ 1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed. 1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck. RIP ElJay RIP 67ChevyRedneck RIP Grumpy Old Man

07-13-2017, 12:38 PM	#12
jeffahart Senior Member Join Date: May 2012 Location: Scottsdale, AZ Posts: 1,902	Re: Strange AC problem? I am running a gates 7555 for the A/C and fan. It squealed a bit at first but after running it a bit I cinched it down again after it settled in . No more pig squeals. __________________ White K20

07-13-2017, 04:26 PM	#14
cleszkie Registered User Join Date: Feb 2003 Location: Santa Ana, CA Posts: 2,191	Re: Strange AC problem? If all else fails, you can take some emory cloth to the pulley grooves to give them some "bite", and to remove any old burnished belt material. I do not recommend using any sort of "belt conditioner" or "belt dressing" to increase belt grip on the pulleys. That stuff just makes a mess, and can make the problem worse in some cases. X2 on the Gates belts.

07-13-2017, 04:23 PM	#15
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,631	Re: Strange AC problem? What is your opinion of belt and hose dressing? I've seen cans and pouches of it at the store and wondered about it. Good? Bad? Waste of time and money or good stuff?

07-17-2017, 06:36 PM	#17
ApacheIvan Registered User Join Date: Nov 2011 Location: Dallas TX. Posts: 1,053	Re: Strange AC problem? Gates 7555 came today, on the truck already, night and day! No more slipping, you can just tell that there is more weight and girth to the belt. Thanks for the recommendation! __________________ Dale - ApacheIvan 1972 Chevy Custom/20 Custom Camper Highlander http://67-72chevytrucks.com/vboard/s...d.php?t=740479 Original Owner Do you have a 1972 Plaid Pickup?

07-17-2017, 07:27 PM	#18
jeffahart Senior Member Join Date: May 2012 Location: Scottsdale, AZ Posts: 1,902	Re: Strange AC problem? I keep a 7355 power steering, 7525 Alternator and the 7555 AC belts hanging from my ceiling for spares. Along with the upper 20607 and the lower 20694 Rad hoses. Because.... that's the way we've always done it around here! __________________ White K20

07-21-2017, 11:23 PM	#19
ApacheIvan Registered User Join Date: Nov 2011 Location: Dallas TX. Posts: 1,053	Re: Strange AC problem? The Gates 7555 belt made all the difference in the world. No more stretching, no more squealing, looks and works great! __________________ Dale - ApacheIvan 1972 Chevy Custom/20 Custom Camper Highlander http://67-72chevytrucks.com/vboard/s...d.php?t=740479 Original Owner Do you have a 1972 Plaid Pickup?



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