73 Air Conditioning
Thread Starter
Intermediate
Joined: May 2010
Posts: 40
Likes: 0
From: San Antonio Texas
73 Air Conditioning
I just bought a 73 and the A/C doesn't work. Everything is there, just doesn't work. No surprise. Is paying to replace/rebuild worth the expense? I've heard that they didn't cool that weel new. I live in Texas.
Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
Definately worth trying to fix. First things to check, try to turn the center of the compressor clutch by hand or with a wrench, if compressor not locked up it should turn. Remove service cap to reveal schrader valve, it looks like a tire stem valve, press center of valve and see if any pressure in system, wear eye protection some oil might come out. If no pressure compressor will not come on as there is a low presure switch that prevents 12v getting to clutch. Ck. this first and post results. There are some good A/C mechanics on Forum. mds...
Last edited by mds3013; May 9, 2010 at 08:15 PM.
Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
My '77 does. It will produce 50 degree air on a 100 degree day. Maintains about 70 degrees in car. Someone may have bypassed the low pressure switch. I think the '73s had them. Next step is to pressurize the system and find the leak. Do you know how long it has been since the A/C worked? mds...
Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
OK. Tell him that if it has not been converted to R134a that you want to keep it R12. R12 is still available. I saw 600lbs. of it at a Delco Supplier last week. R12 cools better than R134a and is what the system was designed for. He will know what needs to be done to the system to get it back into shape. Good Luck with it, mds...
Last edited by mds3013; May 9, 2010 at 08:45 PM.
Safety Car
Joined: Aug 2001
Posts: 3,683
Likes: 201
From: Waterford Mi
If I only new then what I know now. 
I replaced my entire system back in 1994. The 73 was the first year GM used the VIR valve. It has worked ok but every time it does crap out it cost a bundle to fix. I would be very afraid of any parts that you have going bad just because of the age alone. My MPG goes way down when I run my AC because the compressor stays on all the time.
If I were to do it again I would upgrade to a newer system with all new parts.
I still use R12 so it cools just fine for the northern states but it is a lot warmer in Texas.
Just my thoughts on the subject.
Good luck
I replaced my entire system back in 1994. The 73 was the first year GM used the VIR valve. It has worked ok but every time it does crap out it cost a bundle to fix. I would be very afraid of any parts that you have going bad just because of the age alone. My MPG goes way down when I run my AC because the compressor stays on all the time.
If I were to do it again I would upgrade to a newer system with all new parts.
I still use R12 so it cools just fine for the northern states but it is a lot warmer in Texas.
Just my thoughts on the subject.
Good luck
Pro
Joined: Apr 2004
Posts: 594
Likes: 0
From: Gotham City CA
I can't speak for a '73, but mine works great on my '72. I have a new compressor and dryer, plus one new hose and R12. I don't think my wife would be willing to take the trips we take with our club (1200-1800 miles) if we did not have it.
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Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
I have a '73 with the original A6 compressor and the VIR system. It cools fine.
Just as important as getting the system working is to do everything CF members have suggested in other posts to keep the drivetrain heat out of the cabin.
Especially the foam tunnel collar and the tunnel insulation shown in this diagram. My tunnel collar fit tightly so I didn't have to glue it in place.
http://www.zip-corvette.com/ProductD...L2-SR&CTitle=&
Just as important as getting the system working is to do everything CF members have suggested in other posts to keep the drivetrain heat out of the cabin.
Especially the foam tunnel collar and the tunnel insulation shown in this diagram. My tunnel collar fit tightly so I didn't have to glue it in place.
http://www.zip-corvette.com/ProductD...L2-SR&CTitle=&
