Has anyone had a retro fit from R12 to 134a ? Ifso what was the cost and does it cool well?

 

I would not convert from R12 to R134 based on what several mechanics have told me. R134 requires a higher pressure which will wear out the old R12 compressor. R134 is not as "thick" as R12 and you might find leaks after the conversion. And R134 does not cool as well as R12. When cars were required to use R134 in 1994, they had different compressors and bigger condensors supposedly to compensate for the new stuff. Oh yes, R12 is compatible with mineral oil and R134 is compatible with PAG oil. To convert properly, one has to get all of the mineral oil out of the system unless you use Freeze 12 with is nothing more than R134 that is compatible with mineral oil.

 

While I don't agree with everything Sivek says he is correct about Freeze 12. There are other "freons" that are supposed to be better as well as compatiable. Cool Top comes to mind. I am using Freeze 12 in the 85, seems to do an acceptable job.

 

I converted my 92 several years ago and have had no problems.
Cools just fine. After you get someone to pump your old freon out, it only costs $40 ($30 if you find it on sale) for the changeover kit that comes with the new fittings, caps, and all the freon, plus the kit I used had a gauge installed so you won't overfill. I found one guy that only wanted $20 to pump out the old freon on my 76 that I am going to convert. Shop around on getting it pumped out, and you may want to change out the screening filter also, they tend to collect and hold the old R12 oil, they only cost a few bucks.

 

I'm sorry I have to disagree.

It is perfectly ok to convert any known good R12 system to R134a.

The process is relatively easy, take your known good working system to an AC facility or dealer to have the R12 evacuated.

Purchase a InterDynamic 134a conversion kit. It will come with three cans of premixed Artic Freeze R134a and Ester oil. Plus a gage set.

You will refill the system to 80-85% of the R12 fill. This is necessary to compensate for the molecular differences between R12 and R134a and the differences in head pressure. Determining how much is placarded on your R12 system then a calculation is provided with the kits instruction fairly easy, and you determine the quantity based on the pressure of the low side fill.

Any remaining R12 or oil will be pushed to extreme cavities in the hoses, connections, accumulator, etc. as the R134a will displace it.

The R134a system will cool just as effectively, it may perform better depending on if you replace a few components. But any system would improve by replacing certain parts due to wear and tear.

R134a is better for the environment and you can safely service your system afterwards should any component fail down the road. R134a is inexpensive and can be purchased at local autoparts. R12 requires either you obtain a certificate, plus properly handling, or a trip to a service facility. R12 has not been manufacturered since late 1993. It is now very expensive to use, if available in your area.

To improve the performance and efficiency of your AC system regardless of refrigerant, and depending on the time in service:

Replace the condensor, next you can replace the evaporator. Both of these most likely the core fins are clogged. With clogged fins you have less heat transfer and less efficiency.

If you end up with leaks the most likely cause is the o-rings.

If you intend to do the conversion I would recommend the following and the cost will be most like under $150.

Replace the o-rings, evaporator w/new orifice tube and the accumulator. Purchase an extra can of ester oil and in the factory service manual it describes the proper amounts of ester oil to be added to each component for the accumulator, evaporator and compressor if you open the lines to it. For an example it might be 2 1/2 oz for one, 3 oz for another and 3 1/4 oz in another. It won't be more than the can contents. Then coat your o-rings with ester oil and tighten the connections.

You will need to verify you have the proper size wreches to fit all connetions they are very large and different sizes. I belive it is 32mm and 27mm but you should verify first.

If you have the C68 electronic air, you will need to jumper the pressure sensor to override and force the compressor on and to draw in the first can of refrigerant. Afterwards it will operate normally and draw in the remaining amount needed from the last two cans. That is because low freon will set a code and cause the sensor to shut down the compressor, protecting it.

Here are some links for you:

http://www.id-usa.com/

http://www.corvettemagazine.com/2006...conversion.asp


Interdyanmics has some videos on their site to help you.

When my evaporator sprung a leak, I replaced it (it comes with a new orifice tube) and the accumulator and o-rings. The condensor is still in fine condition as well as the compressor. Mine has been working better than it had with R12 and will freeze you out if you set it at 60°F. My car sits in the florida sun at work all day (transparent roof), when I come out it's hot in the car but by the time I'm out of the parking lot it is already cooling down. Within a couple miles the cabin temp is comfortable.

Read the information and make the decision for yourself.

 

When I did the 134 change I dont know how many people told me stuff like, "your compressor will lock up". I did my Camaro 6 years ago and the Vette 3 years ago. Both are still blowing cold.

 

Did my conversion about 3 years ago and it blows so cold in the Vette you could hang a wash cloth off my wife's you know whats, and for that matter mine too. Don't even ask...no pics

I say go for it.

Gary

 

I converted my 90 2 years ago and it works fine. I would recommend changing all the o-rings over to the 134 compatible material, new orifice tube and also flushing the components (not the compressor). This forces you to replace all the oil and it makes sure that as much of the old oil is removed as possible. Even tho it is a HUGE PITA, pull the evaporator housing and make sure there is no crud buildup - leaves mainly but this will allow you to verify its condition.

There are plenty of posts on this forum about the switch with some very good detailed info. Everything I did, I learned from here.

 

The only issue with using a flush, it is a corrosive. And if you don't get it all out of the system, trouble is on the horizon.

 

Given the many types/brands of flush solvent out there I doubt that is the case for all of them. Most claim to be safe and even beneficial in some way. If you have proof to the contrary, I'd like to hear it. I seem to be playing a lot of A/C stuff at home lately and the more info I have the better.

 

I will look for that data.... and update the post.

I'm not saying don't use flushes, I'm just repeating the precaution that it's very important to get it all back out of the system.