pcolt94

The question is what kind of Freon can I add to a R12 system which is not R12 that I can get away with.

The situation is that it is an slightly older GM vehicle than the 84-85 vetts but is basically an identical A/C system. The vehicle does not travel on the roads any more but I only drive it on my properly for towing and such. The A/C did work great with a new compressor for many years but then had a problem with the electrical and the clutch would not engage. I never found or really looked for the problem till now and did repair the bad electrical connection. I don’t think it has worked since about 04-05.

At this point there is not even enough Freon in the system to close the low pressure switch. I did jump the switch out but there is not even enough Freon in there the make the pipes cold. (Static is 25 or less).

So at this point I would like to give it a shot at life and see if I can add Freon and get it running again. The deciding factor here is money. There is no way I am going to add R12 and pay that kind of money when it can leak out or whatever. I will go for a few bucks but not big money.

I know of Freeze 12 and some of the others with their claims of good and bad. If the A/C basically worked I would be happy. Efficiency is not on the top of the list.

I just don’t have any personal experience with these substitute Freon's and just looking for any opinions that will get me up and running without doing any damage. Any direction would be appreciated.

jon0108

i use Autofrost r-12 replacement

Benny42

Pull the compressor and change the oil. Evacuate & recharge with 134a. That's a quicky conversion that will do you fine for a yard tug. Cheap & readily available too.

1986coupe

If you go with the new R-12a (available in many different names) then you can add it to any system. It is cheap and available at most locations. A kit normally comes with an R134a retro fit adaptor for your car.

However, the chemical make up of this newer product means that you can only top off the old stuff. Once this new R-12a is in then you have to purge it each time that you want to add something to it. This is because if the smallest molecule leaks and you simply add more then the percentage of the others will be too great and it won't cool.

Like I said, it is inexpensive and available everywhere.

martymcfly

I had a shop change my 85 to 134. It only worked for 1 summer, then it was empty. Another shop told me that the first shop should have changed the hoses and o-rings when they did the conversion. R12 is a large sized molecule, 134 is such a small molecule that it leaks out of rubber hoses and o-rings. I figure I won't need my ac until next summer, so I will address the issue then. I don't know if it is true or now, this is what the shop told me. They also told me that I would have been better off having the shop change it to freeze12 or hotshot.

engle1147

If the old compressor hasn't turned since '05 then it is highly likely the shaft seal(s) will leak like a sieve once the shaft starts to spin.

Depending on the make/model of the vehicle and the condition of the rest of the existing system (does seem to be holding some gas) - you might be able to get a rebuilt compressor, oriface tube, dryer/accumulator, oil & freon (134) for pretty cheap (under $200 total)

arb905

I used to work on A/C systems, big and small. Take the time to retrofit a 134a system. If you use Freeze-12, you will never be happy. I used to have problems on freezers that were using Freeze-12, they never got cold enough. Or you could find a friend that works on A/C systems and have them get some R-12 for you. They still have some here and there at about $1000 for a 25lb drum. R-134a retrofit would be much cheaper than topping off your system and it will cool better.

Good luck.

SunCr

Zero, Ziltch, NADA, None - there is no refrigerant compatible with any other refrigerant and there is some danger of hurting yourself or someone else when you mix things up. Get your license at www.epatest.com and buy R12 to your heart's content or convert it to R134 properly because if you don't, no one is going to work on your muck-up. Gas will always be the cheapest part of whatever it needs to make it work (and last) and that's probably anywhere from $800 to $1200 in parts if it's all leaked out. The good part is that this isn't rocket science to fix it so if you can work on an engine, you can work on your a/c and save the labor. You'll need some tools, but if it's a one time deal, cheap out on the Harbor Freight stuff and save the change for your gas.

j-wireman

...with SunCr.
Additionally, not every refrigerant is compatible with the oil used in R12 AC systems, R134a being one of them. There are other refrigerants out there that won't be destroyed by the oil used in R12 systems.

As I understand it, an R12 system can NEVER be completely cleaned of its oil. It is in the crevices, the gaskets, everything. The result is that the residual oil will destroy the newly introduced R134a refrigerant.

I may have been told wrong. I will need to see proof otherwise, however.

pcolt94

Pretty well equipped to do my own work. For A/C, have gauges, pump and Freon sniffer plus loads of tools.

I am not in disagreement that R12 is the proper and preferred way to go. But I'm with who said it will probably leak out and would hate to lose the R12. That’s why I thought another gas might be a solution even though it may not cool as well. It will probably never see the hard surface road again and replacing the compressor would be out of the question. If I cannot make it cool so be it. Runs good for moving rocks and trees.

I thought about the idea of pulling a vacuum on it and see if it would hold. If it held, I would be more inclined to put in the R12.

At no point was I considering putting in R134. Was just looking for something that would be compatible with R12 and the system.

SunCr

You could use R134 and there's some literature that suggests residual Mineral Oil helps to seal the hoses but you want everything that you can out of it and then you should use Ester and not PAG (though some replacement compressors - if you're going that far - lose the warranty with Ester). At the very least, you've got to swap out the Accumulator. I'd also pull the compressor and drain what's in it and then flush with 4 ozs of oil, drain and repeat (turn the shaft a dozen or so times in each direction each time you put in the oil). Leave 4 ozs of fresh oil in it and put 4 ozs in a new Accumulator. With an R134 conversion it helps if you can get the fans on sooner - probably around 170 psi (about 1.7 volts from the the Pressure Sensor) - and that will take a reflash, but keeping the upper end under control should give you a vent within 5 or so degrees of the Factory charge. You're fortunate because your Year allows this change - earlier C4's don't and their conversions suffer when the high spirals into the 300's (90 degrees or better at the Condenser).

pcolt94

Appreciate the info But there is no electric fans, computer or anything to flash. I'm' talking basic automotive with a 4 barrel here.

It is not going to get any new parts or a R134 retrofit. I was just hopeful curious that some refrigerant gas it might be able to drop in but obviously now does not seem to be the case.

I checked for any Freon leaks with my sniffer and could not really find anything substantially leaking. Probably just leaked out normally over the last 8 or so years. Maybe I will be lucky and there will be no actual leak.

My new direction is I am going to get the license to buy R12 which I have had bookmarked for 2 years+ now. Seems like R12 is the best and cheapest way to go to get it fixed. Besides, I need it for my 280ZX. The course is kind of fun to go thru, wish I had done it sooner.

Thanks for the incite.

RWDsmoke

Doesn't cost all that much to reseal an older compressor. Good insurance for that expensive R-12.

a bad habit

You might check out Hot Shot but you will need an EPA card to get it.
Just do a recovery on the R12 then pull the system into a deep vacuum. If it holds for 30 minutes without a change in the vacuum reading charge to a PT chart specs. If it does change you got a leak that needs fixed.

SunCr

Don't know of any licensing requirement for Hot Shot. It's 79% R134 with a dash of Butane (but not so much that there's an outright ban), but why not just go with R134?

pcolt94

Can't really disagree, probably the way to go if it was going on the road, it only drives 5 miles or so per year. But willing to take the chance at first and just add R12 and see how it goes

But the biggest update here is I now have my 609 MVAC certification so I can now buy the R12. So when I get ready for step 1, I will try adding Freon and see if it will hold the charge.

pcolt94

So now with my 609 MVAC certificate, I went out buying R12 on eBay. Bought lots of cans so A can support my other R12 car also which does drive about once a week. The interesting thing is nobody really never asked me to produce the 609 certificate.

I added several cans to the GM vehicle one at a time and checked for leaks over a period of days. It's now working blowing cold air. I will see if it hold when summer comes and keeps working. I just think sitting there not working for all those years it naturally seeped out.

This seemed like the easiest resolution.

dunno513

This is the first thing I've read that explains why my converted system shows ester oil. But, it only shows 1 oz of ester. Would there also be PAG oil in the system?

Currently the system is not working. The high side pressure builds until the pressure switch shuts it down. On the gauge it was getting up to about 500 psi. My simple conclusion is a blocked metering valve so once it's apart, new valve and accumulator are going in. Depending on what is blocking the valve will determine if further breakdown is necessary to flush the system.

My plan was to put in a shot(1 oz) of pag oil into the system with the charge to make up for any lost with the old accumulator. But not knowing how the PAG and ester oils work together has me doing a bit more research.

When I pull a vacuum the oil remains.... correct?... So I should only have to make up for about 1/4 of the system total. Anyone else have any insight on why the high side would be over pressurizing other than a blocked metering valve? Should I be mixing the oils... I mean there has to be something other than 1 oz of ester in there right now... but that is all the conversion sticker shows. that and 2 lbs and 25 oz. of R134a We think that last bit is either 2.5 or .25 oz...

Words of wisdom welcome here. Never dealt with a converted system before... just the random bad evap or cond. and always r134a systems.

H P Bushrod

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