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seez52

Anybody know about car A/C?

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seez52    411

Anybody know about car A/C? I'm working on restoring a 64 Rambler and have just installed an all new system (using original evaporator). It's seems to work great, but the new compressor really squalls at rpm's over 3000. Trying to troubleshoot it so I don't damage anything.

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bersaguy    4,695

Sounds like you don't have enough tension on A/C belt. I would look at that first and then I would check and be sure you have not put to much Freon in the system...............JMHO

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No_0ne    786

It's a Rambler.  They were designed for Grandma, who never drove at 3000+ rpm ...

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glock55    277

I suppose this system is an aftermarket add on? If so I would ck the following:

1) what is the head pressure

2) belts for alinement, also that the belt is not running too deep in a pulley. The belt should not run in the bottom of any pulley. The tension can be correct but if belt is to deep it will squeal. Have run across this with aftermarket kits mixed with factory pulleys. A picture of the belt routing might be helpful. 

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Murgatroy    1,166

Belt alignment and tension are the first things I think of.

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seez52    411

It's not a belt squeal. The pulleys are in good alignment and riding high in the grooves. It could be that the belt is too tight. I usually install belts on the tight side when new. I'll adjust that and see if it makes a difference.

The noise is definitely coming from inside the compressor. Pressures: 1500 rpm, 7 low side, 165 hi side at about 85 degrees ambient, vent air is running 46 degrees. I've always thought since charging it that the low side as way too low in comparison to the high side. I had it charged up to about 250 hi side and still the low side was less than 10. Wondering if the expansion valve is not letting enough refrigerant through at higher rpm causing some sort of "starvation" on the compressor suction side?   

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bersaguy    4,695
13 hours ago, seez52 said:

It's not a belt squeal. The pulleys are in good alignment and riding high in the grooves. It could be that the belt is too tight. I usually install belts on the tight side when new. I'll adjust that and see if it makes a difference.

The noise is definitely coming from inside the compressor. Pressures: 1500 rpm, 7 low side, 165 hi side at about 85 degrees ambient, vent air is running 46 degrees. I've always thought since charging it that the low side as way too low in comparison to the high side. I had it charged up to about 250 hi side and still the low side was less than 10. Wondering if the expansion valve is not letting enough refrigerant through at higher rpm causing some sort of "starvation" on the compressor suction side?   

Ok, let me ask you this? I know it might be a stupid question but did you make sure you put at least 4 oz's of Compressor oil in the system? I use to always put in the oil after I pulled a vaccum on the system and would use the gauges to add the oil and then add no more than three cans of freon. Also if your watching the A/C compressor when it is squealing is the clutch turning on the compressor or is it look like it might be stopping and going like it might be trying to recycle as if low on freon. If the expansion valve was mal-functioning you would be getting real high side readings when it is running. If all else fails and it were mine and you have to gauges designed for servicing A/C units and you have access to a vaccum pump I would remove all the freon you have in the system and pull a vaccum until all your gauges read zero. Turn off all gauge valves and begin adding freon back into system. If you added oil first time you should not need to add again as vaccum pump will not remove the compressor oil. Reason for doing this is you may have an air lock in the system and being a closed system it has no way of venting the air lock. When system is operating at normal depending on out side air temps 70-80 degrees, High side should be 190-200 lbs and low side should be 50-60 lbs. Good luck with your Rambler.

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seez52    411
12 minutes ago, bersaguy said:

Ok, let me ask you this? I know it might be a stupid question but did you make sure you put at least 4 oz's of Compressor oil in the system? I use to always put in the oil after I pulled a vaccum on the system and would use the gauges to add the oil and then add no more than three cans of freon. Also if your watching the A/C compressor when it is squealing is the clutch turning on the compressor or is it look like it might be stopping and going like it might be trying to recycle as if low on freon. If the expansion valve was mal-functioning you would be getting real high side readings when it is running. If all else fails and it were mine and you have to gauges designed for servicing A/C units and you have access to a vaccum pump I would remove all the freon you have in the system and pull a vaccum until all your gauges read zero. Turn off all gauge valves and begin adding freon back into system. If you added oil first time you should not need to add again as vaccum pump will not remove the compressor oil. Reason for doing this is you may have an air lock in the system and being a closed system it has no way of venting the air lock. When system is operating at normal depending on out side air temps 70-80 degrees, High side should be 190-200 lbs and low side should be 50-60 lbs. Good luck with your Rambler.

I added about 3 oz of oil. Compressor mfg said it wasn't necessary, but typically with all new components I was thinking 1 oz of oil per new component. So, new condenser, new dryer and completely flushed and cleaned evaporator so I figured 3 oz. The compressor came with oil. 

I initially installed three cans, which seemed like a lot. I was trying to get the low side up but it would never get in the range I thought it should even though the high side kept getting higher. I pulled a vacuum on the system for about 6 hours before filling. Filled some liquid to start through the high side with the compressor not running. It took maybe a whole can almost. Shut that side valve, cranked it up and the pressure was high enough for the compressor to come on. Put the other two cans in through the suction side as gas. 

Edited by seez52

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bersaguy    4,695
5 minutes ago, seez52 said:

I added about 3 oz of oil. Compressor mfg said it wasn't necessary, but typically with all new components I was thinking 1 oz of oil per new component. So, new condenser, new dryer and completely flushed and cleaned evaporator so I figured 3 oz. The compressor came with oil. 

I initially installed three cans, which seemed like a lot. I was trying to get the low side up but it would never get in the range I thought it should even though the high side kept getting higher. I pulled a vacuum on the system for about 6 hours before filling. Filled some liquid to start through the high side with the compressor not running. It took maybe a whole can almost. Shut that side valve, cranked it up and the pressure was high enough for the compressor to come on. Put the other two cans in through the suction side as gas. 

Sounds like you have covered all your bases. I have no other ideas I can offer. Some times this new freon can be a pain in the butt to get it right. My son cusses the stuff all the time trying to get all the equipment to do what it s suppose to do. I was lucky enough that i quit working on cars for a living before that junk came out. I know back when it first came out he was retro-fitting all the older cars to accept the new stuff and it gave him fits for a few years. Hope you get it figured out!

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glock55    277

I would think your using R134A as refrigerant. If so what type of oil did you put in the system. Most 134a uses pag oil although that is changing. Also how much oil did you add. You must add for compressor, dryer and both coils. Your kit should have advised how much to add for dry system. If not dry did you flush old oil as they do not mix. 134a pressures run about 17/25 on low side and 165/185 on high side. The fan should come on around 325, however your probably running a direct drive fan on that car. If low side is low the following should be checked evalve, hoses for frost rings and correct freon charge. Reguarding oil we always drain new compressor then add correct amount accounting for a new dryer also. Lastly make sure belt not too tight. I suppose this system is an aftermarket add on? If so I would ck the following:

1) what is the head pressure

2) belts for alinement, also that the belt is not running too deep in a pulley. The belt should not run in the bottom of any pulley. The tension can be correct but if belt is to deep it will squeal. Have run across this with aftermarket kits mixed with factory pulleys. A picture of the belt routing might be helpful. 

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1fast4by    115

any way you can get a video of this sound?

 

High side pressure sounds close to where is should be, Id prefer to see it a little higher... low side pressure is too low.... But because both sides are a little low like that it would suggest that you do not have sufficient refrigerant in the system.. Expansion valve could also be stuck closed...but I am assuming that it is new.. However, expansion valves are slightly different going from R12 to R134a

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bersaguy    4,695

I have another question. Does the drive belt for the A/C system have an idler pulley as part of the drive belt for A/C? if so did you replace it when you installed the system or is there another device that applies tension to the drive belt. Sometimes it can be the bearings in the idler pulley that causes the noise you may be hearing..........Just a thought?

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seez52    411

there is no idler, it's on the same belt as the power steering and the steering pump moves to create the tension.

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seez52    411
15 hours ago, 1fast4by said:

any way you can get a video of this sound?

 

High side pressure sounds close to where is should be, Id prefer to see it a little higher... low side pressure is too low.... But because both sides are a little low like that it would suggest that you do not have sufficient refrigerant in the system.. Expansion valve could also be stuck closed...but I am assuming that it is new.. However, expansion valves are slightly different going from R12 to R134a

here's a short vid, it's not a belt noise I'm pretty sure.

https://www.amazon.com/photos/share/HEuyE3O20OgmZsGmS1OUMfBbYrt0tfPRy2277bnmMmU

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bersaguy    4,695
4 minutes ago, seez52 said:

here's a short vid, it's not a belt noise I'm pretty sure.

https://www.amazon.com/photos/share/HEuyE3O20OgmZsGmS1OUMfBbYrt0tfPRy2277bnmMmU

Definately, not a belt noise. I didn't really pick out any what you could call unusual noises other than maybe a whine in power Steering pump but not really out of the norm but then my hearing is not what it once was...................:doh:

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1fast4by    115

Dang man, that sounds like the compressor is coming apart..

 

I might try first adding a bit more refrigerant... check the expansion valve. Those pressures arent correct... But it sounds bad, i hope it isnt too late for the compressor.

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RED333    2,305

Use a long rod, wood or metal, put one end on the compressor and the other at your ear. Listen at diff spots on the compressor. Sounds like bearings to me.

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seez52    411
4 hours ago, RED333 said:

Use a long rod, wood or metal, put one end on the compressor and the other at your ear. Listen at diff spots on the compressor. Sounds like bearings to me.

that's a good idea, I have a stethoscope but had not thought of using it.

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