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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: lehman368 on July 10, 2018, 06:20:19 PM

Title: 87 r10 a/c blows cold then warm
Post by: lehman368 on July 10, 2018, 06:20:19 PM
On my 87 a/c blows cold then after running for hour or so it will start warming up and seams the air flow through the vents slows down. When you shut it off it seams to drip a lot of condensation water.


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Title: Re: 87 r10 a/c blows cold then warm
Post by: bd on July 10, 2018, 06:38:41 PM
The evaporator is freezing over.  What are the system pressures?
Title: Re: 87 r10 a/c blows cold then warm
Post by: lehman368 on July 10, 2018, 08:34:46 PM
Quote from: bd on July 10, 2018, 06:38:41 PM
The evaporator is freezing over.  What are the system pressures?




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Title: Re: 87 r10 a/c blows cold then warm
Post by: lehman368 on July 10, 2018, 08:37:54 PM
Quote from: bd on July 10, 2018, 06:38:41 PM
The evaporator is freezing over.  What are the system pressures?
I don’t have a pressure regulator for a/c. If I can find one From a friend I will check. Upper and lower? What pressures should they read at? 


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Title: Re: 87 r10 a/c blows cold then warm
Post by: VileZambonie on July 11, 2018, 05:47:44 PM
If you have access to the proper manifold gauge set, you can monitor your operating pressures and report them back. Has the system been retrofit? What refrigerant is in it?
Title: Re: 87 r10 a/c blows cold then warm
Post by: lehman368 on July 12, 2018, 12:45:23 AM
Quote from: VileZambonie on July 11, 2018, 05:47:44 PM
If you have access to the proper manifold gauge set, you can monitor your operating pressures and report them back. Has the system been retrofit? What refrigerant is in it?
Yes it has been retrofitted before I bought it. It would blow cold last summer but really never drove it on longer than 45min trips. Now after working on the truck this past year. I have been driving it more and taking it on longer trips. Real Big headache last weekend on a 3and 1/2 hour trip in 90 + degree heat. Stoped cooling after about 50 mins.


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Title: 87 r10 a/c blows cold then warm
Post by: lehman368 on July 12, 2018, 12:47:44 AM
Quote from: lehman368 on July 12, 2018, 12:45:23 AM
Quote from: VileZambonie on July 11, 2018, 05:47:44 PM
If you have access to the proper manifold gauge set, you can monitor your operating pressures and report them back. Has the system been retrofit? What refrigerant is in it?
Yes it has been retrofitted before I bought it. It would blow cold last summer but really never drove it on longer than 45min trips. Now after working on the truck this past year. I have been driving it more and taking it on longer trips. Real Big headache last weekend on a 3and 1/2 hour trip in 90 + degree heat. Stoped cooling after about 50 mins.


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The new refrigerant I think. I have not been able to find any one the has proper gages yet. After it thaws out it cools the same. We stopped to eat, when I came back out to the truck there’s a big puddle under it 3x6 foot spot.


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Title: Re: 87 r10 a/c blows cold then warm
Post by: Rapid Roy on July 12, 2018, 06:12:29 AM
Welcome to the site.
Title: Re: 87 r10 a/c blows cold then warm
Post by: Irish_Alley on July 20, 2018, 11:40:12 PM
welcome from maryland, low Freon can cause the core to freeze up but like vile said get a manifold gauge set and see what the readings are