R134 conversion
Thread Starter
Racer
Joined: Jan 2004
Posts: 286
Likes: 1
From: Madison WI
R134 conversion
My 94 AC wasn't working and I checked to see if I had freon and I have nothing in the system and the compressor won't turn on because of it. The C68 didn't give me any codes for low freon, but obviously I have a leak and I'm hoping that a retro kit with new o-rings might fix the leak and give me some AC again. I've read about changing orifices because of the difference in refrigerants and pressures but don't have a clear understanding of what's all needed.
Any help would be appreciated.
Any help would be appreciated.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
My '92 with the original charge of R-12 is still running.
But, when it goes, I'm ready.
I don't think putting R-134a in a system designed for R-12 will be efficient enough in Florida.
So, I've already started to buy the "entire" R-134a system from a '95 to put in my '92.
It is a bolt in.
When mine goes, I figure at a minimum I would need a new accumulator, compressor and evaporator anyway. The evaporator gets plugged with soggy junk. And, looking under the front where the condensor hangs down, the condensor has already been hit with its share of road debris.
So, the only things left to replace is the lines and control switches.
Then, I will have a complete system designed from the ground up for R-134a.
Even the schematic and electrical connectors for the control switches are exactly the same -- it is a plug in swap.
Tom Piper
But, when it goes, I'm ready.
I don't think putting R-134a in a system designed for R-12 will be efficient enough in Florida.
So, I've already started to buy the "entire" R-134a system from a '95 to put in my '92.
It is a bolt in.
When mine goes, I figure at a minimum I would need a new accumulator, compressor and evaporator anyway. The evaporator gets plugged with soggy junk. And, looking under the front where the condensor hangs down, the condensor has already been hit with its share of road debris.
So, the only things left to replace is the lines and control switches.
Then, I will have a complete system designed from the ground up for R-134a.
Even the schematic and electrical connectors for the control switches are exactly the same -- it is a plug in swap.
Tom Piper
Last edited by Tom Piper; May 17, 2006 at 09:35 AM.
Pro
Joined: Jan 2006
Posts: 667
Likes: 1
From: Centennial Colorado
Originally Posted by Toy90
My 94 AC wasn't working and I checked to see if I had freon and I have nothing in the system and the compressor won't turn on because of it. The C68 didn't give me any codes for low freon, but obviously I have a leak and I'm hoping that a retro kit with new o-rings might fix the leak and give me some AC again. I've read about changing orifices because of the difference in refrigerants and pressures but don't have a clear understanding of what's all needed.
Any help would be appreciated.
Any help would be appreciated.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
94's came with R-134a so there is no need for any 'retrofit' kit. Go to a reputable shop that does A/C work and have the system vacuumed and re-charged. IF there is a leaky o-ring, it should show up in the vacuum step. When the system is re-charged, they will add a leak-test dye so any leaks can be traced with an ultra-violet lamp.
If a R-12 system is running witout issues but you still want to go to R-134a, many shops will do a conversion to R-134a and give you credit for the R-12 they remove from the system. The old R-12 can be filtered and reused in other systems.
I had my 87's A/C system converted to R-134a last year and all I needed was a new orifice, adapters for the fill hoses or test guages, and the correct oil and the refrigerant. The dryer was fairly new and didn't need replacing. The original (radial) compressor is working just fine with the R-134a.
As far as efficiency in hot ambient air temps, R-134a doesn't really provide the same cold temps at the outlets that R-12 does, but with the smaller interior of the Vette, about 40 degrees at the outlet is fine. It may take a little longer to cool the car down if it's been sitting outside, but once the inside temp is at the setting you desire, there should be no difference in the cooling you feel.
If a R-12 system is running witout issues but you still want to go to R-134a, many shops will do a conversion to R-134a and give you credit for the R-12 they remove from the system. The old R-12 can be filtered and reused in other systems.
I had my 87's A/C system converted to R-134a last year and all I needed was a new orifice, adapters for the fill hoses or test guages, and the correct oil and the refrigerant. The dryer was fairly new and didn't need replacing. The original (radial) compressor is working just fine with the R-134a.
As far as efficiency in hot ambient air temps, R-134a doesn't really provide the same cold temps at the outlets that R-12 does, but with the smaller interior of the Vette, about 40 degrees at the outlet is fine. It may take a little longer to cool the car down if it's been sitting outside, but once the inside temp is at the setting you desire, there should be no difference in the cooling you feel.
Thread Starter
Racer
Joined: Jan 2004
Posts: 286
Likes: 1
From: Madison WI
Thanks for the help guys. I guess I just assumed I had R12 because the car is 12 years old. I should have checked that first. I'll have a shop find the leak and charge it up for me then.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I was under the impression that the 94s (which I have) came thru with the 134. Should be easy to tell. Obviously the connection fittings are completely different. Basically the R12 is a screw on fitting and the 134 is a snap on. 
