Need Help in SW WA for '86 AC

[Scoobywagon]

That's what I've been hearing. I don't want to retrofit anything, want stock all the way.

 

As a refrigerant, R12 is more efficient than R134A. That is to say it requires less refrigerant to achieve the same cooling effect. However, R12A is even more efficient than R12 and it costs about 1/3 what R12 will cost you. You don't even have to change anything in the system to make it work properly. However, the EPA generally wants to see a conversion taking place, so we usually replace the R12 fittings with R134a fittings which meets their criteria for a "conversion".

 

Now, a lot of things have been said here, so I understand you getting confused. Let me try to clear things up for you.

 

Your car originally shipped with R12. The EPA has gone to a lot of effort to get it out of circulation. It can still be had, but its expensive. R12 will cost you about $80/lb and, as previously mentioned, cannot be bought without a license. R134a is the newer refrigerant. It is not as efficient as R12 and that necessitates some changes in the A/C system in order to accomodate it. Converting a car from R12 to R134a is generally labor intensive and so it can be very expensive to do. But it also means that you can run R134a which costs about $30/lb rather than $80. That fact has led to the development and sale of R12a. R12a is propane-based and so is very cheap. R12a will set you back about $25/6 oz can. Which sounds very expensive until you realize that 6 oz of R12a will provide the same cooling effect as 12 oz of R12 or 16oz of R134a.

 

Your car will require ~10oz of R12a. Since this is an older system and you're putting in a used compressor, you'll want to make sure there's plenty of oil in there. Most systems take ~4 oz of oil. We generally use oil with fluorescent dye in it because it keeps the system, particularly the compressor, lubricated and also gives us a diagnostic tool in the event of a system failure. You should DEFINITELY replace the receiver/drier. And, to elminate any confusion here, the terms receiver/drier and accumulator are somewhat interchangeable. If you go to a parts store and ask for the part by either name, they are likely to know what you want. However, to be completely correct technically, the part in your car is correctly called a receiver/drier.

 

If this were my car, I would replace the oil in the used compressor you are getting with fresh oil. Most compressors ship new from the factory with ~2oz of oil in them. Since yours is not new, you have no way of knowing how much is in there or what condition its in. Drain it and replace it. Put the "new" compressor in place BEFORE you replace the receiver/drier. Any o rings you disturb in this process need to be inspected for flat spots or pinches. If there's even a QUESTION about one of them, replace them all. They're a few cents each and they are EXCELLENT insurance against system failure. Be very careful putting things back together so as to avoid pinching any o-rings. This is also a good time to put the other 2 oz of oil in the system. Once you've got everything put back together, pull the system down to a vacuum. When we do this kind of work, we leave the vac pump running for 20-30 minutes, then make sure it holds 30 inches of vacuum for at least 20-30 minutes. If it does, all is likely good and its time to recharge. I would recharge the system using one can of chemical dessicant (which in this case contains 4 oz of R12a) and one can of R12a. This gives you your 10 oz of refrigerant and the chemical dessicant does a good job of binding any moisture that may be left in the system and converting it to a synthetic lubricant. If you should end up with a slow leak, you can add a can of sytem seal which will help seal up any pin holes in the system and, just like the dessicant, contains 4oz of R12a.

 

If you have any questions, by all means ask away.

[Scoobywagon]

Pardon my small thread hijack, but what is the difference between R12 and R12A?

 

 

R12 is a chlorofluorocarbon (CFC). R12a is a hydrocarbon and, as such, is essentially unregulated as a refrigerant. It is not corrosive in the presence of moisture like R134a. It is less flammable than R12. It is less toxic when burned than either of the other 2. Its mostly propane and butane. Its also more thermally efficient which, in some cases, leads to increased compressor life and improved fuel economy.

[Redcap]

R12 is a chlorofluorocarbon (CFC). R12a is a hydrocarbon and, as such, is essentially unregulated as a refrigerant. It is not corrosive in the presence of moisture like R134a. It is less flammable than R12. It is less toxic when burned than either of the other 2. Its mostly propane and butane. Its also more thermally efficient which, in some cases, leads to increased compressor life and improved fuel economy.

 

Excellent, thank you!

[Subarule]

What a lot of great information! Thank you for taking the time to write this up, and for putting it in an easy-to-follow manner.

 

 

As a refrigerant, R12 is more efficient than R134A. That is to say it requires less refrigerant to achieve the same cooling effect. However, R12A is even more efficient than R12 and it costs about 1/3 what R12 will cost you. You don't even have to change anything in the system to make it work properly. However, the EPA generally wants to see a conversion taking place, so we usually replace the R12 fittings with R134a fittings which meets their criteria for a "conversion".

 

Now, a lot of things have been said here, so I understand you getting confused. Let me try to clear things up for you.

 

Your car originally shipped with R12. The EPA has gone to a lot of effort to get it out of circulation. It can still be had, but its expensive. R12 will cost you about $80/lb and, as previously mentioned, cannot be bought without a license. R134a is the newer refrigerant. It is not as efficient as R12 and that necessitates some changes in the A/C system in order to accomodate it. Converting a car from R12 to R134a is generally labor intensive and so it can be very expensive to do. But it also means that you can run R134a which costs about $30/lb rather than $80. That fact has led to the development and sale of R12a. R12a is propane-based and so is very cheap. R12a will set you back about $25/6 oz can. Which sounds very expensive until you realize that 6 oz of R12a will provide the same cooling effect as 12 oz of R12 or 16oz of R134a.

 

Your car will require ~10oz of R12a. Since this is an older system and you're putting in a used compressor, you'll want to make sure there's plenty of oil in there. Most systems take ~4 oz of oil. We generally use oil with fluorescent dye in it because it keeps the system, particularly the compressor, lubricated and also gives us a diagnostic tool in the event of a system failure. You should DEFINITELY replace the receiver/drier. And, to elminate any confusion here, the terms receiver/drier and accumulator are somewhat interchangeable. If you go to a parts store and ask for the part by either name, they are likely to know what you want. However, to be completely correct technically, the part in your car is correctly called a receiver/drier.

 

If this were my car, I would replace the oil in the used compressor you are getting with fresh oil. Most compressors ship new from the factory with ~2oz of oil in them. Since yours is not new, you have no way of knowing how much is in there or what condition its in. Drain it and replace it. Put the "new" compressor in place BEFORE you replace the receiver/drier. Any o rings you disturb in this process need to be inspected for flat spots or pinches. If there's even a QUESTION about one of them, replace them all. They're a few cents each and they are EXCELLENT insurance against system failure. Be very careful putting things back together so as to avoid pinching any o-rings. This is also a good time to put the other 2 oz of oil in the system. Once you've got everything put back together, pull the system down to a vacuum. When we do this kind of work, we leave the vac pump running for 20-30 minutes, then make sure it holds 30 inches of vacuum for at least 20-30 minutes. If it does, all is likely good and its time to recharge. I would recharge the system using one can of chemical dessicant (which in this case contains 4 oz of R12a) and one can of R12a. This gives you your 10 oz of refrigerant and the chemical dessicant does a good job of binding any moisture that may be left in the system and converting it to a synthetic lubricant. If you should end up with a slow leak, you can add a can of sytem seal which will help seal up any pin holes in the system and, just like the dessicant, contains 4oz of R12a.

 

If you have any questions, by all means ask away.

[STI_Wolf]

Well, turns out I'm not coming to pick up the parts.. Subarule is.. or her sister..

 

I just hope that next time Subarule would have told me this before I made plans, instead of waiting till I was all packed up and ready to go. :-\

 

*sigh*

[Txakura]

"What a lot of great information! Thank you for taking the time to write this up, and for putting it in an easy-to-follow manner."

 

ditto

[subaruguru]

PM sent

 

Rob.

[Subarule]

To all who offered help & advice...

 

I decided to not get my AC fixed. It just didn't seem worth the money I would have had to invest, for something I would use maybe as much as 2 weeks (not even consecutive days) a year.

 

Yes, it would be nice to have AC when the heat gets unbearable, but since I'm retired I can just not drive my car on days of killer temps.

 

I'd rather put the money into other things the car needs.

 

Many thanks to those who were ready to help me with the AC project.