76 Corvette Air Conditioning fix original or replace with aftermarket system ??
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Drifting
Joined: May 2006
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76 Corvette Air Conditioning fix original or replace with aftermarket system ??
Looking at a 76 Vette. The air conditioning does not blow cold. Is it worth fixing the original or should it be replaced with an aftermarket system ??
Race Director
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76 is a VIR system. It can be upgraded and modernised. Or for a heap more money you can put in vintage air.
it's up to you
The original system has many parts that should work just fine. So a complete aftermarket replacement is likely not necessary. Although many do just this and swear it's the best answer, cost be damned!
The VIR system worked very well with the R12 refrigerant of the day. But R12 is difficult to find and expensive when you do. So repairing as per stock standard is possible, but unless your looking for that NCRS perfect original car. Doesn't seem practical to most.
upgrading the car to use a more modern orifice tube set-up. Modern compressor, condenser and dryer can be done without completely gutting the car. As in a complete aftermarket system, evaporator and all.
There is more than one way to skin a cat. One would need to determine the condition of all components before making a informed decision on the best way to attack the problem.
it's up to you
The original system has many parts that should work just fine. So a complete aftermarket replacement is likely not necessary. Although many do just this and swear it's the best answer, cost be damned!
The VIR system worked very well with the R12 refrigerant of the day. But R12 is difficult to find and expensive when you do. So repairing as per stock standard is possible, but unless your looking for that NCRS perfect original car. Doesn't seem practical to most.
upgrading the car to use a more modern orifice tube set-up. Modern compressor, condenser and dryer can be done without completely gutting the car. As in a complete aftermarket system, evaporator and all.
There is more than one way to skin a cat. One would need to determine the condition of all components before making a informed decision on the best way to attack the problem.
Last edited by 4-vettes; Apr 24, 2025 at 04:20 AM.
Le Mans Master
Joined: Mar 2004
Posts: 7,502
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From: Little Rock AR
Depends who is doing the work. If you want to get your feet wet you can get it done cheap yourself. Buy a decent vacuum pump and a set of guages and check it out. If it holds a vacuum well, you might just get lucky.
Compressors can be resealed if they are not scattered. All the rest is a judgement call.
Compressors can be resealed if they are not scattered. All the rest is a judgement call.
Le Mans Master
Joined: Jun 2019
Posts: 7,658
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From: Indiana
unless you know history i would..
- see what gauges say
- does it hold vacuum?
- do you know what refrigerant and or lubricant is in it?
show a bunch of pics on hoses compressor etc.. maybe it has been converted.
Having been where you are. if i had to do it all over..
- flush system
- replace compressor with Sanden compressor.. the old ones are good but they really draw power..
- run available refrigerant and proper oil
- new accumulator
here is a decent article
https://www.motortrend.com/how-to/18...oogle_vignette
too bad you do not have orifice to look at for debris..
All that said i stayed r12 and replace OEM style compressor and accumulator. Still running since.
not exactly same as yours but here is my latest update.
https://www.corvetteforum.com/forums...questions.html
- see what gauges say
- does it hold vacuum?
- do you know what refrigerant and or lubricant is in it?
show a bunch of pics on hoses compressor etc.. maybe it has been converted.
Having been where you are. if i had to do it all over..
- flush system
- replace compressor with Sanden compressor.. the old ones are good but they really draw power..
- run available refrigerant and proper oil
- new accumulator
here is a decent article
https://www.motortrend.com/how-to/18...oogle_vignette
too bad you do not have orifice to look at for debris..
All that said i stayed r12 and replace OEM style compressor and accumulator. Still running since.
not exactly same as yours but here is my latest update.
https://www.corvetteforum.com/forums...questions.html
Last edited by interpon; Apr 24, 2025 at 09:54 AM.
Safety Car
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St. Jude Donor '09 thru '26
for what it's worth, my story on my 1969 renovation. the a/c system that was on my car when it was purchased was not connected to anything but the refrigerant hoses and was seized completely, all the components of the system were worthless (and the heater core was shot). it would have been a major investment to try to put it all back together again compared to the price of a more efficient replacement system, so i priced out several of the major "after market" systems and decided to go with a vintage air replacement system that not only included a more efficient style compressor, but a much smaller footprint under the dash for the HVAC complete system it wound up actually costing a bit less that a complete restoration of the OEM HVAC system that was in my car, and i was guaranteed a much more efficient updated technology system. i do believe that i was also swayed by the fact that the OEM a/c system on my 78 pace car was just "ok" as far as it's cooling capacity particularly in the dog days of summer which was when it saw it's most service. i agree that you should probably exhaust all possibilities of repairing what you have in order to make a valued decision regarding the way to go, but price it all out and you will see that there probably isn't that much of a difference in upgrading to current technology and the customer service i received from the vintage air folks was excellent. just another opinion.
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I get that. If I buy this 50 year old car what am I getting into?
Truthfully, the air-con is likely to be the least of your worries on a 50 year old vehicle.
As I believe I already stated, the VIR system worked very well back in the 70's when that refrigerant was readily available. Some people find cans of it on Ebay and the like and purchase these vintage cans of refrigerant and DIY their air-con.
Common problem is the system isn't adjustable to different types of refrigerant. So you can convert it over to modern gas. But it won't be great. In fact, it won't be acceptable.
So, you can convert it. I have a excellent thread on here discussing the process of converting the system over.
Just Google corvette 73-E77 Air-Con upgrade. It should pop right up and take you back to this forum.
A 50 year old system could have any one of a number of problems. So a nice, simple answer to your question just isn't possible.
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Race Director
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I think if you purchase the car. You will find a list of things that actually NEED to be fixed. You can of course speculate that it might need a heater core.
If you are a very handy guy and love working on old cars.
Dive in. We are all here to help with knowledge and advice.
If you are looking at a vintage Corvette and want to pay a mechanic to repair every little thing. You should be prepared to spend far more than the cost of the car to keep it maintained.
If you are a very handy guy and love working on old cars.
Dive in. We are all here to help with knowledge and advice.
If you are looking at a vintage Corvette and want to pay a mechanic to repair every little thing. You should be prepared to spend far more than the cost of the car to keep it maintained.
Last edited by 4-vettes; Apr 25, 2025 at 12:12 AM.
Team Owner
Joined: Jan 2006
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From: Crossville TN
Is this car special enough (or inexpensive enough) to justify putting another $2K into it for an A/C upgrade? That's what it will cost for a decent conversion kit with new modern compressor and R134a system. Plus a lot of work to get that done (the $2K is for the hardware...not the labor).
Maybe a different car with a working A/C system would be a better choice.
Maybe a different car with a working A/C system would be a better choice.
Team Owner
Joined: Jul 2004
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From: Redondo Beach, California
I got rid of my factory air to make sure I didn't have interference with my headers that I was going to buy. Also, the factory air is very inefficient....the cold air plenum is adjacent to the exhaust manifolds. With Vintage Air, the cold air plenum is inside the car, under the horizontal dashboard. The factory cold air plenum is probably an inch away from the cast iron exhaust manifold. On my 70, the heat from the exhaust manifold had burn a hole in the cold air plenum.
The A6 wobble plate compressor in these GM cars is really a great compressor. It has a lot of cooling capacity and is very reliable. Too bad it's so damn heavy. Wish they'd made an aluminum version with iron sleeves for the compressor. These compressors were used in Rolls Royces, Bentleys, MBs etc. Since the interior of Corvettes were easier to cool that a full sized GM sedan of the 60's and early 70's, their A6 compressors were reduced in capacity to decrease their HP drag on the engine. These compressors had reduced compression ratios.
The A6 wobble plate compressor in these GM cars is really a great compressor. It has a lot of cooling capacity and is very reliable. Too bad it's so damn heavy. Wish they'd made an aluminum version with iron sleeves for the compressor. These compressors were used in Rolls Royces, Bentleys, MBs etc. Since the interior of Corvettes were easier to cool that a full sized GM sedan of the 60's and early 70's, their A6 compressors were reduced in capacity to decrease their HP drag on the engine. These compressors had reduced compression ratios.
Racer
Joined: May 2025
Posts: 348
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From: Georgia
for what it's worth, my story on my 1969 renovation. the a/c system that was on my car when it was purchased was not connected to anything but the refrigerant hoses and was seized completely, all the components of the system were worthless (and the heater core was shot). it would have been a major investment to try to put it all back together again compared to the price of a more efficient replacement system, so i priced out several of the major "after market" systems and decided to go with a vintage air replacement system that not only included a more efficient style compressor, but a much smaller footprint under the dash for the HVAC complete system it wound up actually costing a bit less that a complete restoration of the OEM HVAC system that was in my car, and i was guaranteed a much more efficient updated technology system. i do believe that i was also swayed by the fact that the OEM a/c system on my 78 pace car was just "ok" as far as it's cooling capacity particularly in the dog days of summer which was when it saw it's most service. i agree that you should probably exhaust all possibilities of repairing what you have in order to make a valued decision regarding the way to go, but price it all out and you will see that there probably isn't that much of a difference in upgrading to current technology and the customer service i received from the vintage air folks was excellent. just another opinion.
Great decision making Post. Gracias
Le Mans Master
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The A6 wobble plate compressor in these GM cars is really a great compressor. It has a lot of cooling capacity and is very reliable. Too bad it's so damn heavy. Wish they'd made an aluminum version with iron sleeves for the compressor. These compressors were used in Rolls Royces, Bentleys, MBs etc. Since the interior of Corvettes were easier to cool that a full sized GM sedan of the 60's and early 70's, their A6 compressors were reduced in capacity to decrease their HP drag on the engine. These compressors had reduced compression ratios.