Squealing AC belt
07-18-2018, 10:35 AM
#1
Instructor
Thread Starter
Squealing AC belt
1981 Corvette.
So, this whole saga began when the previous owner said that the A/C worked, but needs a charge. I know what that really means.
Anyway, I eventually found a hole in the low pressure pipe coming off of the compressor (metal part) and I patched that with some JB Weld and some tape that supposedly had a tear pressure of 4400 PSI. After adding some cans of R134 (Yes, it had been converted), the clutch started to engage and the A/C started working. But then, it started squealing. I tried tightening the belt by moving the Compressor out on it's brace a bit. That partially worked, but it seemed like the clutch was just all of a sudden stopping. So, I added one of those oil charges. and more freon. Worked great, squealing stopped. JB Weld and tape did not hold, so I blew oil and freon out of a tiny pinhole in the pipe.
So, I got this stuff called JB Weld Plastic and slathered it on there, then got a special rubber/nylon tube from some industrial company and covered the mess with a piece of tube and some hose clamps.
Started putting in more freon. I discovered another pinhole when the pressure got about 25 psi. Plugged and capped that one off. Cleaned everything up and started again. No signs of leaks anywhere. At this point I am running out of freon cans, and my pressure is right around the 40 psi mark (in the blue zone on the guage). Air is blowing nice and cold inside, Compressor clutch is working constantly, things look great.
I get in the car for a test drive and as soon as I shift into reverse, the squealing starts.
Now, I've watched the compressor when the clutch kicks on and the whole thing shifts. I am thinking there has to be some other points of adjustment that I can't see, since I have the adjustment bolt all the way to the end of the bracket now on the rear of the compressor, and the belt only stays tight until I run the A/C again. Then I turn the car off, check the belt and it is floppy again.
So, any other point I need to look for to keep this bracket tight? One on the head and one that disappears under the air cleaner somewhere? Do I add any extra compressor oil? Some shot out with the leaks, but I have no idea how much, and don't want to add too much oil.
One a side note, I have an electric fan attached to the radiator in front of the clutch fan. So far, nothing I have done will make it turn on. Was it computer controlled, and now that the computer is unhooked I need to set up a switch?
I was sitting in unusually bad traffic yesterday afternoon with no A/C and I was being roasted alive, so I would like to get this all sorted out.
Thanks for any input!
So, this whole saga began when the previous owner said that the A/C worked, but needs a charge. I know what that really means.
Anyway, I eventually found a hole in the low pressure pipe coming off of the compressor (metal part) and I patched that with some JB Weld and some tape that supposedly had a tear pressure of 4400 PSI. After adding some cans of R134 (Yes, it had been converted), the clutch started to engage and the A/C started working. But then, it started squealing. I tried tightening the belt by moving the Compressor out on it's brace a bit. That partially worked, but it seemed like the clutch was just all of a sudden stopping. So, I added one of those oil charges. and more freon. Worked great, squealing stopped. JB Weld and tape did not hold, so I blew oil and freon out of a tiny pinhole in the pipe.
So, I got this stuff called JB Weld Plastic and slathered it on there, then got a special rubber/nylon tube from some industrial company and covered the mess with a piece of tube and some hose clamps.
Started putting in more freon. I discovered another pinhole when the pressure got about 25 psi. Plugged and capped that one off. Cleaned everything up and started again. No signs of leaks anywhere. At this point I am running out of freon cans, and my pressure is right around the 40 psi mark (in the blue zone on the guage). Air is blowing nice and cold inside, Compressor clutch is working constantly, things look great.
I get in the car for a test drive and as soon as I shift into reverse, the squealing starts.
Now, I've watched the compressor when the clutch kicks on and the whole thing shifts. I am thinking there has to be some other points of adjustment that I can't see, since I have the adjustment bolt all the way to the end of the bracket now on the rear of the compressor, and the belt only stays tight until I run the A/C again. Then I turn the car off, check the belt and it is floppy again.
So, any other point I need to look for to keep this bracket tight? One on the head and one that disappears under the air cleaner somewhere? Do I add any extra compressor oil? Some shot out with the leaks, but I have no idea how much, and don't want to add too much oil.
One a side note, I have an electric fan attached to the radiator in front of the clutch fan. So far, nothing I have done will make it turn on. Was it computer controlled, and now that the computer is unhooked I need to set up a switch?
I was sitting in unusually bad traffic yesterday afternoon with no A/C and I was being roasted alive, so I would like to get this all sorted out.
Thanks for any input!
07-18-2018, 11:01 AM
#2
Team Owner
Member Since: Jun 2000
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Do you have the correct AC belt and is it routed correctly? The electric fan is not computer controlled and uses a temp sensor at the rear of the passenger's side head.
07-18-2018, 11:47 AM
#3
Safety Car
1981 Corvette.
So, this whole saga began when the previous owner said that the A/C worked, but needs a charge. I know what that really means.
Anyway, I eventually found a hole in the low pressure pipe coming off of the compressor (metal part) and I patched that with some JB Weld and some tape that supposedly had a tear pressure of 4400 PSI. After adding some cans of R134 (Yes, it had been converted), the clutch started to engage and the A/C started working. But then, it started squealing. I tried tightening the belt by moving the Compressor out on it's brace a bit. That partially worked, but it seemed like the clutch was just all of a sudden stopping. So, I added one of those oil charges. and more freon. Worked great, squealing stopped. JB Weld and tape did not hold, so I blew oil and freon out of a tiny pinhole in the pipe.
So, I got this stuff called JB Weld Plastic and slathered it on there, then got a special rubber/nylon tube from some industrial company and covered the mess with a piece of tube and some hose clamps.
Started putting in more freon. I discovered another pinhole when the pressure got about 25 psi. Plugged and capped that one off. Cleaned everything up and started again. No signs of leaks anywhere. At this point I am running out of freon cans, and my pressure is right around the 40 psi mark (in the blue zone on the guage). Air is blowing nice and cold inside, Compressor clutch is working constantly, things look great.
I get in the car for a test drive and as soon as I shift into reverse, the squealing starts.
Now, I've watched the compressor when the clutch kicks on and the whole thing shifts. I am thinking there has to be some other points of adjustment that I can't see, since I have the adjustment bolt all the way to the end of the bracket now on the rear of the compressor, and the belt only stays tight until I run the A/C again. Then I turn the car off, check the belt and it is floppy again.
So, any other point I need to look for to keep this bracket tight? One on the head and one that disappears under the air cleaner somewhere? Do I add any extra compressor oil? Some shot out with the leaks, but I have no idea how much, and don't want to add too much oil.
One a side note, I have an electric fan attached to the radiator in front of the clutch fan. So far, nothing I have done will make it turn on. Was it computer controlled, and now that the computer is unhooked I need to set up a switch?
I was sitting in unusually bad traffic yesterday afternoon with no A/C and I was being roasted alive, so I would like to get this all sorted out.
Thanks for any input!
So, this whole saga began when the previous owner said that the A/C worked, but needs a charge. I know what that really means.
Anyway, I eventually found a hole in the low pressure pipe coming off of the compressor (metal part) and I patched that with some JB Weld and some tape that supposedly had a tear pressure of 4400 PSI. After adding some cans of R134 (Yes, it had been converted), the clutch started to engage and the A/C started working. But then, it started squealing. I tried tightening the belt by moving the Compressor out on it's brace a bit. That partially worked, but it seemed like the clutch was just all of a sudden stopping. So, I added one of those oil charges. and more freon. Worked great, squealing stopped. JB Weld and tape did not hold, so I blew oil and freon out of a tiny pinhole in the pipe.
So, I got this stuff called JB Weld Plastic and slathered it on there, then got a special rubber/nylon tube from some industrial company and covered the mess with a piece of tube and some hose clamps.
Started putting in more freon. I discovered another pinhole when the pressure got about 25 psi. Plugged and capped that one off. Cleaned everything up and started again. No signs of leaks anywhere. At this point I am running out of freon cans, and my pressure is right around the 40 psi mark (in the blue zone on the guage). Air is blowing nice and cold inside, Compressor clutch is working constantly, things look great.
I get in the car for a test drive and as soon as I shift into reverse, the squealing starts.
Now, I've watched the compressor when the clutch kicks on and the whole thing shifts. I am thinking there has to be some other points of adjustment that I can't see, since I have the adjustment bolt all the way to the end of the bracket now on the rear of the compressor, and the belt only stays tight until I run the A/C again. Then I turn the car off, check the belt and it is floppy again.
So, any other point I need to look for to keep this bracket tight? One on the head and one that disappears under the air cleaner somewhere? Do I add any extra compressor oil? Some shot out with the leaks, but I have no idea how much, and don't want to add too much oil.
One a side note, I have an electric fan attached to the radiator in front of the clutch fan. So far, nothing I have done will make it turn on. Was it computer controlled, and now that the computer is unhooked I need to set up a switch?
I was sitting in unusually bad traffic yesterday afternoon with no A/C and I was being roasted alive, so I would like to get this all sorted out.
Thanks for any input!
the electric fan is controlled by a thermostat located above the starter. It is set for 235 degrees. You can buy a lower stat at 195.
If you have an over heating problem, this would cause very high pressure in you ac unit and cause leaks but if your hoses are just old or the system has been open to the atmosphere for a long time, it will need a complete overhaul.
07-18-2018, 02:39 PM
#4
Instructor
Thread Starter
Oh, ok. Thanks. I don't think my car has ever reached that temp, so that might be why I never see it run. I thought maybe it was disconnected, assuming it was an aux fan for when the ac kicked on.
The whole thing had been professionally converted to R134 about 6 years ago, so I think the hoses and whatnot should still be ok.
The bolt is not slipping on the adjuster, but I have noticed that when I loosen thing, then tighten it down, I get about half an inch of wobble on the top part of the belt, but if I reach for the bottom of the belt near the crank pulley, I can move it a good two inches or more. I think the belt may be stretched. When it is running, I bet that slack slowly creeps up and makes the whole thing loose. It's still weird that when the compressor engages, I can see it move a bit.
I have two different fill hoses, and both have gauges giving different readings, but they both show 35-40 psi when the compressor is running, which puts it just short of the halfway point in the blue zone. I don't think that's overfill, but they are pretty generic gauges. I have read where people are filling up to the 50-55 psi range, but honestly, I have never looked up how much pressure it should have, just a roundabout measure of how many ounces an R12 to 134 conversion should hold.
I have a feeling I am going to need to find a replacement belt for the compressor. From looking at it, the power steering (and I use that term loosely) belt needs to come off before I can get to the ac belt.
The whole thing had been professionally converted to R134 about 6 years ago, so I think the hoses and whatnot should still be ok.
The bolt is not slipping on the adjuster, but I have noticed that when I loosen thing, then tighten it down, I get about half an inch of wobble on the top part of the belt, but if I reach for the bottom of the belt near the crank pulley, I can move it a good two inches or more. I think the belt may be stretched. When it is running, I bet that slack slowly creeps up and makes the whole thing loose. It's still weird that when the compressor engages, I can see it move a bit.
I have two different fill hoses, and both have gauges giving different readings, but they both show 35-40 psi when the compressor is running, which puts it just short of the halfway point in the blue zone. I don't think that's overfill, but they are pretty generic gauges. I have read where people are filling up to the 50-55 psi range, but honestly, I have never looked up how much pressure it should have, just a roundabout measure of how many ounces an R12 to 134 conversion should hold.
I have a feeling I am going to need to find a replacement belt for the compressor. From looking at it, the power steering (and I use that term loosely) belt needs to come off before I can get to the ac belt.
Last edited by DVAST8R_88; 07-18-2018 at 02:40 PM. Reason: Adding some info.
07-18-2018, 04:07 PM
#5
Melting Slicks
Oh, ok. Thanks. I don't think my car has ever reached that temp, so that might be why I never see it run. I thought maybe it was disconnected, assuming it was an aux fan for when the ac kicked on.
The whole thing had been professionally converted to R134 about 6 years ago, so I think the hoses and whatnot should still be ok.
The bolt is not slipping on the adjuster, but I have noticed that when I loosen thing, then tighten it down, I get about half an inch of wobble on the top part of the belt, but if I reach for the bottom of the belt near the crank pulley, I can move it a good two inches or more. I think the belt may be stretched. When it is running, I bet that slack slowly creeps up and makes the whole thing loose. It's still weird that when the compressor engages, I can see it move a bit.
I have two different fill hoses, and both have gauges giving different readings, but they both show 35-40 psi when the compressor is running, which puts it just short of the halfway point in the blue zone. I don't think that's overfill, but they are pretty generic gauges. I have read where people are filling up to the 50-55 psi range, but honestly, I have never looked up how much pressure it should have, just a roundabout measure of how many ounces an R12 to 134 conversion should hold.
I have a feeling I am going to need to find a replacement belt for the compressor. From looking at it, the power steering (and I use that term loosely) belt needs to come off before I can get to the ac belt.
The whole thing had been professionally converted to R134 about 6 years ago, so I think the hoses and whatnot should still be ok.
The bolt is not slipping on the adjuster, but I have noticed that when I loosen thing, then tighten it down, I get about half an inch of wobble on the top part of the belt, but if I reach for the bottom of the belt near the crank pulley, I can move it a good two inches or more. I think the belt may be stretched. When it is running, I bet that slack slowly creeps up and makes the whole thing loose. It's still weird that when the compressor engages, I can see it move a bit.
I have two different fill hoses, and both have gauges giving different readings, but they both show 35-40 psi when the compressor is running, which puts it just short of the halfway point in the blue zone. I don't think that's overfill, but they are pretty generic gauges. I have read where people are filling up to the 50-55 psi range, but honestly, I have never looked up how much pressure it should have, just a roundabout measure of how many ounces an R12 to 134 conversion should hold.
I have a feeling I am going to need to find a replacement belt for the compressor. From looking at it, the power steering (and I use that term loosely) belt needs to come off before I can get to the ac belt.
Correct low side pressure is dependent upon ambient (outside) temperature.
Also keep in mind that when you turn the system off the low side and high side equalize to the same pressure so your leak band-aid must withstand a much higher pressure than you're looking at on the gauge.
Perhaps your belt is just glazed and needs replacing.
FWIW: There should be a front and rear compressor hold down bolt.
07-19-2018, 08:12 AM
#6
Instructor
Thread Starter
It looks like my local Auto Zone actually has a replacement belt in stock for $7. I think I can risk it and try it out.
My first attempt at a band-aid was a miserable failure, but this second time around it seems to be holding just fine. Might be due to the fact that I really cleaned the metal before applying the epoxy, and then I did the epoxy in several layers instead of one glob.
We will see! Fortunately, I have another car with working air for my daily work commute when it is 90+ outside.
My first attempt at a band-aid was a miserable failure, but this second time around it seems to be holding just fine. Might be due to the fact that I really cleaned the metal before applying the epoxy, and then I did the epoxy in several layers instead of one glob.
We will see! Fortunately, I have another car with working air for my daily work commute when it is 90+ outside.