R134a changeover
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
R134a changeover
My R12 system needs charging. Interdynamics site says you can change over to R134a without having to change o-rings, hoses, etc. because they use ester oil rather than pag oil and is compatible with any residual R12 oil. So, question is, do you have to pull a vacuum or can you just charge up with the 134 if the system just "happens to be emply"?
Racer
Joined: Jan 2003
Posts: 383
Likes: 0
From: Columbia SC
Yes you can.
Would I ? no,
Why, cause the R12 mineral oil is not compatible with R134a and it will not stay suspended. So what happens when the R12 oil does not stay suspended ? it separates and pools at the highest point in the A/C system, the evaporator.
Now I am by no means the expert on this, but more and more people and books say the same thing.
This is why it is important to get all of the old R12 oil out of the coils and hoses.
Will the old O rings leak with R134a ? Yes they will. Is this a big deal ? no I dont think so, but while your in there getting the old oil out you might as well install new blue O rings right.
Do you really have to replace the rubber hoses in the A/C system ? no, they may or may not leak depending on who you ask.
read this thread:
http://forums.corvetteforum.com/showthread.php?t=887121
Would I ? no,
Why, cause the R12 mineral oil is not compatible with R134a and it will not stay suspended. So what happens when the R12 oil does not stay suspended ? it separates and pools at the highest point in the A/C system, the evaporator.
Now I am by no means the expert on this, but more and more people and books say the same thing.
This is why it is important to get all of the old R12 oil out of the coils and hoses.
Will the old O rings leak with R134a ? Yes they will. Is this a big deal ? no I dont think so, but while your in there getting the old oil out you might as well install new blue O rings right.
Do you really have to replace the rubber hoses in the A/C system ? no, they may or may not leak depending on who you ask.
read this thread:
http://forums.corvetteforum.com/showthread.php?t=887121
Last edited by Pete76Shark; Sep 20, 2004 at 04:59 PM.
Pro
Joined: Mar 2004
Posts: 584
Likes: 0
From: Okemos MI
Originally Posted by carnut114
I have done about 6 chang overs using the kit from walmart. Just made sure it was empty and put it in.
Eric
Eric
he also told me that my compressor clutch was way out of adjustment. 
does anyone know how to adjust these or where to find AC serviceing information?
Thanks, John
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Dec 2003
Posts: 263
Likes: 0
From: Kernersville Nc
Originally Posted by Lotus76
Eric, have you done this on Corvettes? I bought one of those Walmart kits and took the vette to an AC shop to have the R12 removed and he told me it was empty then tried to talk me out of going to 134A, he says it will not be cold. he also told me that my compressor clutch was way out of adjustment.
does anyone know how to adjust these or where to find AC serviceing information?
Thanks, John
he also told me that my compressor clutch was way out of adjustment. does anyone know how to adjust these or where to find AC serviceing information?
Thanks, John
Eric
Instructor
Joined: Aug 2003
Posts: 223
Likes: 0
From: South MS
I've done the conversion to 134a on a (79'Bronco, 90'Mustang, 86'Maxima, 72'Mustang).
I just put the new stuff in. It worked fine everytime, just as cold, and no leaks if you didn't have any before.
A couple of these vehicles have been going 3yrs or more. The 134a kits/cans are so cheap, just do it and you prob wont have any problems.
You don't want to pay a lot for r12.....it won't be long bfore you can't find it on ebay or anywhere.
I just put the new stuff in. It worked fine everytime, just as cold, and no leaks if you didn't have any before.
A couple of these vehicles have been going 3yrs or more. The 134a kits/cans are so cheap, just do it and you prob wont have any problems.
You don't want to pay a lot for r12.....it won't be long bfore you can't find it on ebay or anywhere.
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
There will be others that cringe but my friend "converted" his 73 BB by adding two cans of R-134a, one can of oil, and one can of stop leak to his original a/c system. He didn't pull a vacuum, didn't purge the old stuff, nuttin! Still works like a champ two years later.
When my 79 Mercedes, my daily driver, blew an a/c hose, I replaced the hose, used my Mity Vac to pull a vacuum (took about 11 gazillion pumps) and then refilled with one can of stop leak, one can of 134 oil, and two cans of R-134a. The a/c works VERY well inspite of reports that 134 doesn't cool as well and despite the fact that neither of us did any converting other than add the new stuff.
Third case. My nephew bought his grandpa's GMC work van, a 93 3/4 ton I think. The a/c didn't work. What recipe do you think I used to get it up and running? Yep! One can of stop leak, one can of 134 oil, two cans of R-134a. Three months later, it is still cooling off his van nicely.
Gary
When my 79 Mercedes, my daily driver, blew an a/c hose, I replaced the hose, used my Mity Vac to pull a vacuum (took about 11 gazillion pumps) and then refilled with one can of stop leak, one can of 134 oil, and two cans of R-134a. The a/c works VERY well inspite of reports that 134 doesn't cool as well and despite the fact that neither of us did any converting other than add the new stuff.
Third case. My nephew bought his grandpa's GMC work van, a 93 3/4 ton I think. The a/c didn't work. What recipe do you think I used to get it up and running? Yep! One can of stop leak, one can of 134 oil, two cans of R-134a. Three months later, it is still cooling off his van nicely.
Gary
Racer
Joined: Aug 2004
Posts: 470
Likes: 0
From: South Florida
Originally Posted by djunod
Larry82, just have them recharge it with R12... don't do the conversion. It's just colder & more staying power... of course there are others that have fooled themselves into believing otherwise
I did the conversion on a '79. I wish I never had! The factory system is just not efficient enough for the R134. In the south florida sun and humidity, the converted factory system just can not keep up. I measured the cabin temperature before and after the conversion and based on my experience you can expect about an 8 degree (F) difference.
Safety Car
Joined: Jun 2002
Posts: 4,756
Likes: 2,506
From: Buckeye, AZ
St. Jude Donor '12-'13
Be aware that there are now environment safe R12 formulas (R12A) R12A is $15 a pound (a typical Vette uses 3lbs.) R12A can be intermixed with R12 and has the same properities as R12. I had mine done by a local hot rod shop who would do either the R134A update or simply add R12A. His advice was to go R12A as he claimed R12 still blows colder than R134. He claims that he has had great success with conversions, but felt I would be just as well off to stay R12 and it is cheaper than the conversion using the R12A. I read many articles on R12A prior to doing this and was convinced. This is not highly publicized because lots of shops and stores are making lots of money on conversion kits and conversion.
Racer
Joined: Feb 2000
Posts: 394
Likes: 0
From: Evans GA
Thanks for the tip gliot1!!! I just drained the R12 from my Mako so that I could do get the A/C components out of the way... wasn't looking forward to the cost of refilling it with R12 again...
Do you have a link for online ordering of R12A?
Thanks!!!
Do you have a link for online ordering of R12A?
Thanks!!!
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
[QUOTE=flaskier99
I did the conversion on a '79. I wish I never had! The factory system is just not efficient enough for the R134. In the south florida sun and humidity, the converted factory system just can not keep up. I measured the cabin temperature before and after the conversion and based on my experience you can expect about an 8 degree (F) difference.[/QUOTE]
I had my GM Goodwrench friend convert mine to R134 and it does run a few degrees warmer than I expected. But since it was not working when I originally got it, I can't tell for sure. I do know its not as cool as my liking but is OK. 
I did the conversion on a '79. I wish I never had! The factory system is just not efficient enough for the R134. In the south florida sun and humidity, the converted factory system just can not keep up. I measured the cabin temperature before and after the conversion and based on my experience you can expect about an 8 degree (F) difference.[/QUOTE]
I had my GM Goodwrench friend convert mine to R134 and it does run a few degrees warmer than I expected. But since it was not working when I originally got it, I can't tell for sure. I do know its not as cool as my liking but is OK.
Last edited by marshrat99; Sep 22, 2004 at 12:24 PM.
Pro
Joined: Mar 2004
Posts: 584
Likes: 0
From: Okemos MI
Originally Posted by gliot1
Be aware that there are now environment safe R12 formulas (R12A) R12A is $15 a pound (a typical Vette uses 3lbs.) R12A can be intermixed with R12 and has the same properities as R12. I had mine done by a local hot rod shop who would do either the R134A update or simply add R12A. His advice was to go R12A as he claimed R12 still blows colder than R134. He claims that he has had great success with conversions, but felt I would be just as well off to stay R12 and it is cheaper than the conversion using the R12A. I read many articles on R12A prior to doing this and was convinced. This is not highly publicized because lots of shops and stores are making lots of money on conversion kits and conversion.
I would be very interested in getting more info on R12A. I purchased my vette with the system empty but closed so I am looking at what would be the best option.
Please send me a link if you have one.
Anyone know how to adjust the compressor clutch?
Thanks, John
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
Somewhat on topic, what is the max pressure reading when recharging an R12 system?
ANother hint I picked up, on pulling a vacuum. Just connect the chargin hole to the low pressure and the other end to a vacuum port on the engine. Will pull an adequate vacuum when running a higher rpm to clean out system. Yes, freon, oil charge, water vapor will be sucked into engine, but not enought at once to make any difference.
ANother hint I picked up, on pulling a vacuum. Just connect the chargin hole to the low pressure and the other end to a vacuum port on the engine. Will pull an adequate vacuum when running a higher rpm to clean out system. Yes, freon, oil charge, water vapor will be sucked into engine, but not enought at once to make any difference.
