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lost my cool

perry on Wed July 01, 2009 4:26 AM User is offline

Year: 1996
Make: chevrolet
Model: astro
Engine Size: 4.3
Refrigerant Type: 134
Ambient Temp: 90
Pressure Low: 25
Pressure High: 175
Country of Origin: United States

This astro van has always had the best a/c of any vehicle I have ever owned. 115F across the desert and people asked to turn the air down. The last trip we used the van and noticed the rear factory air was blowing hot. The front air was the normal cold. Later the front air grew warm and I turned off the system and drove back with the windows down and ac off. next morning I ran the ac and the front was cool and the back hot. Rear system does not have a heater core in it. Fan speeds all work and no restriction in the return air duct. Inlet on the condensor was very hot, condensor outlet was warm. After the front went warm the receiver/dryer was warm as was the front evaporator. Compressor was noisy but not a real loud noise. Compressor clutch was engaged when front was cooling and rear was not. when front stopped cooling compressor would cycle high 175 low 25 then turn off. It would cycle on when high went to 150 and low at 45. In 200,000 miles system was opened once, 9 years ago and at 100,000 miles. Complressor seized during a heat wave in Calif. No one could service it, because of the backlog of customers all needing service because of the extreme heat. With the help of the NAPA dealer in my hometown in Arizona he was able to locate a new Delco compressor at a NAPA store in the LA area at a very good price. A call to the ac shop in Globe, AZ gave me enough info to use the new compressor as an idler pulley to operate the altenator and water pump to get back to Arizona. 115 F across the desert at 2:00 AM.. In the 50's and 60's as a kid our family made that trip with nothing more than an igloo can of cool water to drink. The ac shop in Globe rebuilt the system and it has worked for 9 years and 100,000 more miles..Unfortunatly the family that had the shop retired a few years ago. It was one of those shops that you would trust with your life and it has been hard to find another one to replace them. Since the ac shop closed I have gained some experience in minor ac repair on our other vehicles, ie. pressure switches, receiver/dryers, hoses. With a little diagnostic help I think I can give the Astro a new lease on life. Where is the best place to start?

Chick on Wed July 01, 2009 6:44 AM User is offlineView users profile

Sounds like you have a leak, have the system checked, recover and recharge to the factory amount, and add UV dye if you can't see the leak, Charge it up, then run it until the dye shows up.. Your pressures are low for that ambient, so a leak is the most probable.. Hope this helps.

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

perry on Wed July 15, 2009 8:07 PM User is offline

Same astro.1996 dual air ambient 95 vent 93 Pressures high idle compressor on 175, compressor off 150, low pressure with compressor on draws down to 25 psi, low pressure cut out switch turns compressor off. pressure then rises to 48psi and low pressure switch cycles compressor on. At normal engine idle the pressures are the same execpt that the cycling is slower. As per Chick I recovered the 134a, pulled a vaccuum for 2 hours added UV dye and recharged the recommended 3 lbs 134a as stated on the ac tag on the blower box. I found no leaks.But before recovering the pressures on the gauges were 100 with engine off. After the 2 hour vaccuum I closed gauge valves and left it hooked up over night. There was no change in the vaccuum in the morning. I then pulled a vaccuum for an additional 2 hours. I then added the freon. new virgin freon with no additives. I even checked the pressures with another set of gauges and got the same pressure results and the same cycling results. I even changed the low pressure cut out switch with one that I had and got the same results.To clarify I only recovered once and recharged once. Recovered last night, held vaccuum over night and revaccuumed and recharged this morning. Still no cool .

Chick on Wed July 15, 2009 8:39 PM User is offlineView users profile

Did you pull the O tube and check for debris, your compressor may have went south, should be signs of it on the O tube..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

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