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1976 Corvette reccomendation for R-12 or 134

kenimpzoom on Fri August 12, 2011 3:35 PM User is offline

Year: 1976
Make: Chevy
Model: Corvette
Engine Size: 350
Ambient Temp: 100F

Ok, I have read a little bit, but just wanted to get a bit more advice.

First off, I am a DIY guy and hate to take it to a shop to get things fixed. Nothing personal against pros, I just like to work on my own cars.

History: I had the AC system charged with R-12 by a pro. He pulled a vacuum for about 2 hours and said it held a good vacuum and didnt see any leaks. Then he charged it up. It never quite cooled right, but I have heard that Vette AC systems never blow really cold air anyway, so I never took it back. It kept me ok, but it wasnt ice like newer cars. Anyway, by the time next summer rolled around, the R-12 all leaked out. I never charged it up.

Now I was looking into getting the AC working again. I dont need ice cooling, the most important is making it easy to recharge the unit as I doubt I will ever totally eliminate all the leaks. I hate to go back to the shop to get R-12 cause that just gets expensive.

Anyway, I was looking at the VIR eliminator kits, and converting to R-134. I know I need to do a bit of flushing, I dont mind.

Will I get horrible cooling with the VIR eliminator, or will it be "good enough".

This isnt a daily driver, but I do quite a bit of driving with it.

Any thoughts or comments will be welcome.

Thanks, Ken

70monte on Fri August 12, 2011 5:10 PM User is offline

Most people would suggest keeping R12 cars, R12. I have also heard that R134a retrofits on corvette's don't usually come out that great so if that is true, you probably won't be happy with the performance.

If it was my car, I would keep it R12 but I have a 50lb bottle of R12 that is mostly full. A few years ago I got my 609 certificate and was able to buy some cans of R12 off of Ebay so I could keep the system on my 92 Cavalier R12. I know there is still a ton of R12 on ebay so that might be an option for you.


JJM on Fri August 12, 2011 8:46 PM User is offline

Agree with Wayne. Corvette systems were marginal with R-12, and perform poorly with R-134a without significant modifications.

As for VIR eliminator kits, they function best when placed behind one the rear wheels and the vehicle is shifted into reverse. I never understood the urge to replace a superior component with a piece of crap that makes the A6 clack on and off, reducing efficiency and compressor life. GM only went with CCOT in 1977 to save money and weight, the heck with performance.

The system should be flushed dry, dessicant in the EEVIR replaced along with all O-rings (might also consider replacing hoses due to age), and the correct amount of 525 mineral oil and R-12 added. That's the only way to ensure the system will function at peak performance.


When considering your next auto A/C purchase, please consider the site that supports you:

fonebone on Fri August 12, 2011 8:53 PM User is offline

Hi Ken; I used to work on those back then. Those who have will say the same thing---keep it r-12. Don't even entertain the thought of converting to r-134. Do not use the VIR converter. You have a good system with the VIR unit. I went GM school on that rig. Compact and easy to maintain. The converter will cycle your A-6 Harrison compressor so much you'll blow the clutch facings off. It was not designed to cycle continuously, clutch was too small for constant cycling. Go on the net and look up"609 Certification". Take the on line test. You will then be sent a 609 card that you can use to purchase r-12. Then, read the info FAQS on this site to learn how to maintain your own stuff. Do a search here on "VIR" to read a lot of info pertaining to this unique unit. Purchasing a good set of gages and whatever else you might need(from the good folks here who provide so much help) will pay dividends for years! Napa has a "VIR" kit that has a new dryer bag and o-rings. Check this site first though, they can probably get it for you. I liked the VIR so much I converted my daily work car '79 Caprice A/C to it years ago and it runs good and cold still. If I owned a '76, 2 things I'd do--1, an aluminum radiator, 2, an r-134 after market aluminum condenser. Both would go a long way to lower under hood temps and cool you better. Just my thoughts, hope this helps.

Edited: Fri August 12, 2011 at 9:01 PM by fonebone

70monte on Fri August 12, 2011 10:29 PM User is offline

I forgot to mention that I got my 609 certification through the link on this website titled "MACS 609 certification" in the procedures, tips and FAQ forum right below this forum on the main menu. It was an easy process and well worth the $20.


kenimpzoom on Sat August 13, 2011 9:57 PM User is offline

Thanks guys. I am going to stick with the R-12. Will order the new dessicant and o-rings. Gonna check out the MACS 609 certification, that sounds like a great idea.

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