a/c question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Scott Johnson · 05-04-2003, 09:27 PM

Just put a new a/c comp. and drier on my 71 today. Vacuumed the system and recharged but its still not cooling great. Should I have replaced the expansion valve or the poa valve? What do these 2 parts do? I don`t think this system has an orifice tube. Any help would be greatly appreciated.

Class of 69 · 05-04-2003, 09:42 PM

The POA valve regulates how much freon gets into the evaporator,thus how much latent heat can be removed. If it is stuck,you may not be getting full cooling capacity. You would need to watch the pressure gauges for a while to see if the pressures vary to determine if the valve is operating.

Scott Johnson · 05-05-2003, 07:48 AM

Thanks for the reply, does anyone know if you can just clean up the poa and expansion valve, or do they need to be replaced. Is there any other part I need to check before I recharge. The a/c was cooling fine last week until my compressor went out on friday.

Thanks Scott

sam's 72 · 05-05-2003, 08:06 AM

There is a kit out there that you can get. It does away with the POA valve, and exspansion valve, and dryer up front. it put the dryer right there by the evaporator, and it come with orfice tube, and high and low pressure switches, and wireing horness for these switches. You might want to check it out. This is the same set up on later model trucks. By the way, are you still useing R12 or did you swap over to 34a?
Sam

onetoncrewcab · 05-05-2003, 08:50 AM

Yeah...that was my question too. Are you using R12 or 34a? We've converted two vehicles over to 34a and neither one of them blew cold air like it did with the R12.
Mike

Chevy Wrench · 05-05-2003, 09:06 AM

If you have launched your compressor, YOU NEED TO REPLACE YOUR CONDENSER. Flushing the system will not get all of the metal out. Also, your reciever/ drier will have particles in it. Need to replace that as well. I would also replace the expansion valve. Its cheap insurance, if you dont, you will buy another compressor really soon.

Scott Johnson · 05-05-2003, 11:24 AM

I am using 134 and have replaced the drier. Where can I get the kit that does away with the expansion valve. I am going to be putting air on my burb in the future and that might be a good thing to do. Thanks for all the replies, I think I`ll replace the expansion valve and see if it helps. The compressor started making noise and I shut the system down, it was still cooling good, I think maybe the clutch went out.

Class of 69 · 05-05-2003, 03:09 PM

Classic Industries has the POA eliminator kit. I'm not sure who else...check the parts venders on the home page of this board. Be aware that 134, at it's best, won't cool as good as R12.

05-04-2003, 09:27 PM	#1
Scott Johnson Junior Member Join Date: Feb 2003 Location: Louisiana Posts: 281	a/c question Just put a new a/c comp. and drier on my 71 today. Vacuumed the system and recharged but its still not cooling great. Should I have replaced the expansion valve or the poa valve? What do these 2 parts do? I don`t think this system has an orifice tube. Any help would be greatly appreciated. __________________ 71 C10 Step Daily Driver 72 K10 Suburban Work in Progress www.louisianaclassictruckclub.com

05-04-2003, 09:42 PM	#2
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	The POA valve regulates how much freon gets into the evaporator,thus how much latent heat can be removed. If it is stuck,you may not be getting full cooling capacity. You would need to watch the pressure gauges for a while to see if the pressures vary to determine if the valve is operating. __________________ 69 GMC K10 ..some restoration required....still..

05-05-2003, 07:48 AM	#3
Scott Johnson Junior Member Join Date: Feb 2003 Location: Louisiana Posts: 281	Thanks for the reply, does anyone know if you can just clean up the poa and expansion valve, or do they need to be replaced. Is there any other part I need to check before I recharge. The a/c was cooling fine last week until my compressor went out on friday. Thanks Scott __________________ 71 C10 Step Daily Driver 72 K10 Suburban Work in Progress www.louisianaclassictruckclub.com

05-05-2003, 08:06 AM	#4
sam's 72 Senior Member Join Date: Nov 2001 Location: Pasadena, Texas, USA Posts: 1,005	There is a kit out there that you can get. It does away with the POA valve, and exspansion valve, and dryer up front. it put the dryer right there by the evaporator, and it come with orfice tube, and high and low pressure switches, and wireing horness for these switches. You might want to check it out. This is the same set up on later model trucks. By the way, are you still useing R12 or did you swap over to 34a? Sam __________________ 72 LWB chevy truck. Pasadena, Texas

05-05-2003, 08:50 AM	#5
onetoncrewcab One of my kids. Cute eh? Join Date: Oct 2001 Location: Mitchell, SD Posts: 1,286	Yeah...that was my question too. Are you using R12 or 34a? We've converted two vehicles over to 34a and neither one of them blew cold air like it did with the R12. Mike __________________ If a kid asks where rain comes from, I think a cute thing to tell him is “God is crying.” And if he asks why God is crying, another cute thing to tell him is “Probably because of something you did. John 3:16 2006 Chevy HHR 2000 Dodge Durango 1985 Jeep CJ-7 1970 Chevy Pickup

05-05-2003, 09:06 AM	#6
Chevy Wrench former desert rat Join Date: Feb 2003 Location: salt lake city, utah Home of the 3 M's Mormons, methlabs and minivans Posts: 320	If you have launched your compressor, YOU NEED TO REPLACE YOUR CONDENSER. Flushing the system will not get all of the metal out. Also, your reciever/ drier will have particles in it. Need to replace that as well. I would also replace the expansion valve. Its cheap insurance, if you dont, you will buy another compressor really soon. __________________ 94 Chevy Silverado Ext cab 4/6 drop w/ 18's and 2500watt system (work truck). 67 Chevy swb under const. frame off custom, 20's, bagged and a large rat under the hood,and a 1940 Chevy truck under const.

05-05-2003, 11:24 AM	#7
Scott Johnson Junior Member Join Date: Feb 2003 Location: Louisiana Posts: 281	I am using 134 and have replaced the drier. Where can I get the kit that does away with the expansion valve. I am going to be putting air on my burb in the future and that might be a good thing to do. Thanks for all the replies, I think I`ll replace the expansion valve and see if it helps. The compressor started making noise and I shut the system down, it was still cooling good, I think maybe the clutch went out. __________________ 71 C10 Step Daily Driver 72 K10 Suburban Work in Progress www.louisianaclassictruckclub.com

05-05-2003, 03:09 PM	#8
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	Classic Industries has the POA eliminator kit. I'm not sure who else...check the parts venders on the home page of this board. Be aware that 134, at it's best, won't cool as good as R12. __________________ 69 GMC K10 ..some restoration required....still..



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