AC
Racer
Joined: Oct 2000
Posts: 311
Likes: 0
From: West Newton PA
Re: AC (30yr Wait)
No, you can get it evacuated and recharged, but it's getting more and more expensive. I would change over to the new refridgerant. It doesn't sound like too bad of a job. It's got to be cheaper than getting it recharged with R-12.
Burning Brakes
Joined: Aug 1999
Posts: 774
Likes: 0
From: Palatine IL
Re: AC (30yr Wait)
Yes you need the R-134a fittings if you go with the new R-134a refrigerant. R-134a is a lot cheaper!
I converted the R-12 system to R-134a and here is a quick summary:
* Buy a R-134a retro fit kit. It usually has the connectors, compressor oil, o-rings, and orifice tube.
* Take to a shop to evacuate old R-12.
* Install new parts if needed. I needed a hose and the compressor
* Replace accumulator/dryer (looks like a aluminum thermos)
* Install fittings install orifice tube
* Have a shop flush system of old R-12 and oil
* Have shop pressure check and fill system with R-134a
I converted the R-12 system to R-134a and here is a quick summary:
* Buy a R-134a retro fit kit. It usually has the connectors, compressor oil, o-rings, and orifice tube.
* Take to a shop to evacuate old R-12.
* Install new parts if needed. I needed a hose and the compressor
* Replace accumulator/dryer (looks like a aluminum thermos)
* Install fittings install orifice tube
* Have a shop flush system of old R-12 and oil
* Have shop pressure check and fill system with R-134a
Le Mans Master
Joined: Apr 2001
Posts: 5,305
Likes: 9
From: Weston FL
Re: AC (vettesite)
I just went through this with one of my cars and went through 2 yrs ago with my other car. Stick to R12; no need to convert and get less cold air.
I had to go to a local shop to get a rebuilt a/c compressor installed on one of my GM cars and they have a refrigerant that is equivalent to R12 and it isn't R134 and there was no need to change seals. Call around...it took 3 of the little bottles to fill my system after they installed the new accumulater and compressor.
On my prior experience (GN) the prior owner had converted it to R134 and it didn't cool enough. I went to a shop , paid for the R12 and now she cools great.
When you "convert" all you are doing is changing seals so it doesn't leak, but the compressor and everything else a/c - wise was made for R12, so the compressor isn't going to be as efficient.
I had to go to a local shop to get a rebuilt a/c compressor installed on one of my GM cars and they have a refrigerant that is equivalent to R12 and it isn't R134 and there was no need to change seals. Call around...it took 3 of the little bottles to fill my system after they installed the new accumulater and compressor.
On my prior experience (GN) the prior owner had converted it to R134 and it didn't cool enough. I went to a shop , paid for the R12 and now she cools great.
When you "convert" all you are doing is changing seals so it doesn't leak, but the compressor and everything else a/c - wise was made for R12, so the compressor isn't going to be as efficient.
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Race Director
Joined: Sep 1999
Posts: 11,358
Likes: 379
From: Plano TX
Re: AC (yosshimura)
The C3 AC system is perfectly adequate. The reason cars converted to R134a do not cool well is that they have not done the necessary adjustments for R134a. The temp/pressure relationship is different for R134a vs R12. When converting you need to lower the evaporator pressure.
On early cars with the expansion/POA valve setup the POA valve should be adjusted 1/4 turn CCW. On the later CCOT systems, the orifice tube should be replaced with a "smart VOV" (variable orifice valve) and the low pressure cycling switch adjusted 2-4 PSI lower.
Just popping R134a into my '71 yielded 52F vent temps on a 90F day (spec is 48-52). Within spec, but not great. Doing the POA adjustment lowered it to 42F, well beyond spec.
I have some more info on my website.
On early cars with the expansion/POA valve setup the POA valve should be adjusted 1/4 turn CCW. On the later CCOT systems, the orifice tube should be replaced with a "smart VOV" (variable orifice valve) and the low pressure cycling switch adjusted 2-4 PSI lower.
Just popping R134a into my '71 yielded 52F vent temps on a 90F day (spec is 48-52). Within spec, but not great. Doing the POA adjustment lowered it to 42F, well beyond spec.
I have some more info on my website.