quote Originally posted by Dennis LaGrua: Boy this post seems to have generated many pros and cons about the R-13A conversion. I still see this retrofit as the right way to go. I am very haapy with the results that I have obtained but I don't live in Texas!!!! Some forum members seem to advocate the use of FREEZE-12 as a drop in replacement. This refrigerent may work but being a mixture of four different gases, it has different leakage characterisitics than either R-12 or R-134. Develop a leak with Freeze 12 and it renders the remaining charge useless. You must remove the remaining refrigerent. The four components of this gas are of different weights and densities so they do not leak out equally. A small leak ruins the remaining charge so you can't just "top it off". Freeze 12 is also flammable as it contains Butane, the same stuff used in cigarette lighters.

This post generated has generated a great deal of interest and I am learning a great deal about Car A/C. But I am still undecided what to do. A quick peak at an EPA website I saw revealed Freeze 12 to be a mixture of 80% R134a and 20% 142b. That is inconsistent with the information above so I am scratching my head.

I do agree that there are no true drop in replacements for R12. All substitutes require draining the system of remaining Refrigerant before charging. Any you are right, they recommend that in the event of a leak the system be drained before attempting to recharge. Which you would probably want to do anyway to repair the leak.

If only someone from Texas or the southwest could stand up and tell me they are happy with their R134a system I would be encouraged. Anyone????

Well, I'm not from TX or the Southwest, and for those of you talking about the Mason/Dixon line, well, KS was split in the civil war.

BUT, we commonly see temperatures of well over 100 degrees F during the summer and I have changed over about 15 systems in everything from farm tractors to semi's to our '85 Fiero.

Most all of the information that's been given here is pretty correct. You should change the orifice tube if you want the best results. It's a simple procedure and easy to do, you have the line out anyway putting in the new O rings.

You do not need a new condensor or evaporator. In all my conversions, I've never replaced one (due to the 134 anyway, leaks and cracks are another issue not related).

A couple of things, the Fiero seems to blow some pretty good airflow through the system. That is a very good thing for a 134 conversion. The systems I'm not real satisfied with are those that have low airflow through the evaporator. What one could tolerate before with R-12 just won't work with R-134.

Second, idling and low speed will affect your cooling more with R134, especially if you have underdrive pulleys. Again, it's just less tolerant of things that are not up to snuff and low compressor rpm is one of those things.

All that said, we converted the '85 yesterday. I'd already put a new compressor on it when the engine/cradle was out and replaced the O rings in the back. We did the front O rings, the orifice tube, and a new accumulator. I added 3 oz of oil (since the compressor I used already had 134 compatible oil) to the accumulator and another ounce to the evaporator. Pulled a vacuum for about 20 minutes and it held vacuum for 15. The inlet air temperature yesterday (engine idling with underdrive pulleys) was 87 degrees F (I had the hood cracked just a bit to force the system to draw in hot air) and the outlet temperature was 42 degrees F. I'm sure on the road I would have had outlet temps around 38 or so. Pressures were 28# low side and 225# high side. That was just a bit higher than I like to see given the day, but not that far off. The charge was 41 oz. I started watching my pressures pretty close at 32 oz. and that's where it ended up. I will check them again on a good, hot day because I feel I might be slightly overcharged.

It hasn't been hot enough here to say if I'm satisfied with the results in the Fiero yet, but it's one of the conversions that I'm comfortable with based on the airflow, temps, and pressures.

quote Originally posted by jscott1: This post generated has generated a great deal of interest and I am learning a great deal about Car A/C. But I am still undecided what to do. A quick peak at an EPA website I saw revealed Freeze 12 to be a mixture of 80% R134a and 20% 142b. That is inconsistent with the information above so I am scratching my head. I do agree that there are no true drop in replacements for R12. All substitutes require draining the system of remaining Refrigerant before charging. Any you are right, they recommend that in the event of a leak the system be drained before attempting to recharge. Which you would probably want to do anyway to repair the leak. If only someone from Texas or the southwest could stand up and tell me they are happy with their R134a system I would be encouraged. Anyone????

quote Originally posted by jstricker: ...All that said, we converted the '85 yesterday. I'd already put a new compressor on it when the engine/cradle was out and replaced the O rings in the back. We did the front O rings, the orifice tube, and a new accumulator. I added 3 oz of oil (since the compressor I used already had 134 compatible oil) to the accumulator and another ounce to the evaporator. Pulled a vacuum for about 20 minutes and it held vacuum for 15.

What I'm hearing is that to guarantee good results with an R134a conversion you really have to have a tight system, a good, (read new) compressor, change the o-rings and orifice tube, and very carefully pull a vacuum and charge the system.

This does not sound cheap or doable by the average person/air conditioning newbie.

For a system that has already leaked out the R12 it seems unlikely that it will retain the R134a without repairs.

I was hoping that a few cans of R134a blindly loaded with some stop leak would work, but I guess not. So I'm back to square one. I can't find an inexpensive way to get a leaky R12 system back on line. I guess I have to accept that.

Thanks for the report from somewhere near the Mason/Dixon line

[This message has been edited by jscott1 (edited 05-22-2002).]

You don't necessarily have to change your compressor, you need to find your leaks and fix them. Unless your compressor is locked up or leaking by the front seal, I wouldn't change it. I did change ours but that was because it was leaking pretty badly by the front seal and not because of the 134 conversion.

Anybody handy with tools should be able to change the O rings and orifice tube. If you do a good job on that part of it I have yet to see a repair shop turn anyone away from just evacuating and charging the system for you so you don't have to buy or rent a vacuum pump.

You need a tight system no matter what refrigerant you use and that part you can pretty much take care of yourself. The conversion kit, with O rings and oil and adapter fittings, costs ~$50, the accumulator about the same, the orifice tube much less, and the rest is your sweat equity changing things over. I don't consider $125-$150 an outrageous sum of money to do the job right.

quote Originally posted by jscott1: What I'm hearing is that to guarantee good results with an R134a conversion you really have to have a tight system, a good, (read new) compressor, change the o-rings and orifice tube, and very carefully pull a vacuum and charge the system. This does not sound cheap or doable by the average person/air conditioning newbie. For a system that has already leaked out the R12 it seems unlikely that it will retain the R134a without repairs. I was hoping that a few cans of R134a blindly loaded with some stop leak would work, but I guess not. So I'm back to square one. I can't find an inexpensive way to get a leaky R12 system back on line. I guess I have to accept that. Thanks for the report from somewhere near the Mason/Dixon line [This message has been edited by jscott1 (edited 05-22-2002).]

Well, I live south of the Mason-Dixon line, so I'll chime in on this one. I've converted (among other types of cars) two Fieros to R-134. One was an 84 with the DA6 compressor and the other was an 88 with the HR6 compressor. Both conversions were done using new O rings, accumulators, and orifice tubes. The oil was changed and the systems evacuated and charged. The 84 was done about 4 years ago and I have no complaints at all about it's performance. Even sitting in Atlanta traffic on a nice hot summer day with high humidity it puts out lots of nice cold air. I did the 88 last summer, and it also works just fine. (I did have a lot lower volume of air flow than the 84, but it was probably caused by the volume of leaves I found covering about 1/3 of the face of the evaporator.) When I get the 88 back together in the next month or so, I should see a big improvement.

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Rod Schneider, Woodstock, Ga.
White 88 GT :)

quote Originally posted by jstricker: The conversion kit, with O rings and oil and adapter fittings, costs ~$50, the accumulator about the same, the orifice tube much less, and the rest is your sweat equity changing things over.

Okay I'm getting encouraged again, but where do I get the O-rings, accumulator and orifice tube? That's not a part of any conversion kit I have seen. Anybody have part numbers and a site to order them from? Thanks.

You can get them from several places locally. I know Carquest has them. I'd be surprised if Autozone or Pep Boys doesn't as well. If all else fails, The Fiero Store has them as well. Includes the new fittings, O-rings, and Oil. Be sure to look at your compresser real close. If it's oily around the front pulley area, your front seal is probably leaking. It takes special tools to change it out and most of the time will still leak. (The leak is a symptom of another problem normally, not the problem itself) R-134 will leak out faster than R-12 so what you might have been able to get away with before you won't with 134. Good Luck on the swap. Just take it step by step and pretty soon you'll be done.

John Stricker

quote Originally posted by jscott1: Okay I'm getting encouraged again, but where do I get the O-rings, accumulator and orifice tube? That's not a part of any conversion kit I have seen. Anybody have part numbers and a site to order them from? Thanks.

Advance Auto, at least here, stocks MotorMite's "COOL Aide!" line and just about everything else you need. They are the only one in my area that had stuff in stock this time of year. Autozone sent everything back to the warehouse in the fall. Pep Boys wasn't much better.

Okay, I finally decided that an A/C conversion to R134a is beyond my skill level so Proud-1 just underwent a professional conversion for big $$$$, (new compressor, Accumulator/Drier, Expansion Orifice, etc).

So just for fun I decided to use the Interdynamics Retrofit kit on Proud-2, (which was completely bone dry of refrigerant), and Viola' Ice Cold Air. I just blindly shot in 2 1/2 cans and so far it is working great.

Moral of the story, there is no right way to retrofit a Fiero to R134a.

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1988 Coupe
Fiero - It's like an Actual Miniature Car

[This message has been edited by jscott1 (edited 06-09-2002).]

My reman HR6 compressor does not have the high pressure cuttof switch connectors on the back. It does have the pressure relief valve tho. Thew switch will cuttoff the compressor if the pressure gets too high.

Are all HR6 compressors like this?

There are parts you can get (if I can ever find a supplier) to allow you to retrofit a high pressure switch to converted systems without those switches on the compressor.
GM part nos are:
15981985 and 15985307 (ac delco parts are 15-5514 and 15-30467).
Has anyone used these as part of a retrofit and if so where did you get them from and where do they install on the system?
If not then what do peple do about the high pressure cuttof switch on systems that do not have them?
Where does the cuttoff switch connect of HR6 based systems?

Anyone got any pics?

Thanks

Dave E http://www.ltlfrari.com

I did mine the redneck way. The R-12 was gone, so I popped an adapter on and squirted 2 cans of R-134a in followed by 1 can of oil. I followed that with 1 more can of R-134a and it blows 40-45 degrees. Have not had any problems yet.

I live in the St. Louis MO area (north of the Mason-Dixon line), but let me assure you, it gets HOT and HUMID here in the summer. We will see temps in the 100s and humidity levels of near 100% with clear skies for the next few months. We'll see what happens...

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"Its a Fiero thing... Heck, even I don't understand!"

Timothy E. Smith
1986 SE V6 Up and running again!!
1984 Coupe
1996 Ford Probe GT
1999 Chevrolet Silverado Z71
1975 Chevrolet ElCamino SS

R134a the only way to go.........in my opinion. I would also add that when I use this refrigerant in older cars like ours it is especially important in hotter climates to replace the orifice with a special ADJUSTABLE ORIFICE TUBE that allows better cooling at low rpms. Four seasons carries this but I don't know the part #. Just ask the salesperson to look in the illustration book and find the auto adjustable orifice tube. It costs about $20.

Phil

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GTDude
25 years GM experience

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[This message has been edited by tesmith66 (edited 06-10-2002).]

quote Originally posted by tesmith66: I did mine the redneck way. The R-12 was gone, so I popped an adapter on and squirted 2 cans of R-134a in followed by 1 can of oil. I followed that with 1 more can of R-134a and it blows 40-45 degrees. Have not had any problems yet.

The redneck way is getting my vote...since I tried it and it worked, (so far) If it goes a month I will be happy.

The nice thing about the kit I used is that the oil and R134a was premixed in the correct proportion. Eliminated some of the guess work.

On vehicles with orifice tube A/C systems, replacing the orifice tube can improve cooling performance with R134a. One aftermarket part that can really help here is a "Smart VOV" (variable orifice valve) replacement orifice tube. The size of the orifice changes depending on engine speed and system pressure to maximize cooling performance. The valve can supposedly improve R134a cooling performance by 5 to 10 degrees at idle. One source for this device is Car Care Parts in Tampa, FL (1-888-566-5782).

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stock black 87GT auto TTop