So I recently found a local shop that will recharge R12 systems, the 134a runs 20bucks a pound and the R12 is 40 a pound. Another a/c shop told me that if you do a system with 134 and you lose half a pound then the system wont cool at all, but if you are running R12 you can lose up to a pound and a half in the 2.5lb system and it will still have cooling power so my question is should I just stick with the R12 after i replace my compressor, accumulator and orifice tube instead of retrofitting for the 134a?

If you just low -- recharge --- be sure it's true 12 & not freeze 12 -- Get what you pay for --- If system is "empty" look into a 134 conversion. (freeze 12 is a blended refrigerent & is considered a "drop in" for freon 12) I'm running it in my fiero with great results but you can bet the pro's and con's will come in soon . Plenty of info using the search feature. PS if you chose to run a blend--- MARK your system accordingly. Don't screw up the next shops equipment.

quote Originally posted by steve308: If you just low -- recharge --- be sure it's true 12 & not freeze 12 -- Get what you pay for --- If system is "empty" look into a 134 conversion. PS if you chose to run a blend--- MARK your system accordingly. Don't screw up the next shops equipment.

x2

Make sure you know what you are getting. If you have a system that still has R12 in it and it is just low, it can be filled up with R12 but make sure what the shop is adding is R12 and not an R12 replacement. NEVER mix refrigerants regardless of what the label says. Like the previous poster said, you could ruin someone's shop equipment if you do so and have someone else service your car that doesn't know what you have in the system. This could cost the shop and you a lot of money in repairs and possibly fines.

If your system is completely empty or so much has leaked out there isn't enough in there to turn it on anymore, you might as well do the full-blown R134a conversion. Concerning leaks and whether or not a system will still work when low, you need to understand that if you have a leak, you have a problem that needs to be fixed. A leak in an A/C system usually allows all of the oil to leak out first which will result in compressor damage in a very short time. So any leak you may have needs to be repaired. Simply 'adding a can a year' isn't the proper way of doing things and you aren't doing your car any favors by nursing a problem.

A proper conversion over to R-134a involves removing the compressor and draining all of the old oil out of it. Replace any seals that are leaking or replace the compressor. Remove and discard the old oriface tube and dryer/accumulator. Flush out the rest of the system and ensure all flush liquid is removed and the system is 100% dry. Replace any leaking O-rings and replace all o-rings and seals on components you remove or replace (compressor, orifice tube line, accumulator). You can use a factory-Fiero oriface tube to replace the one you took out for use with R134a but there are other/better choices out there. I'm using a variable oriface valve which increases system performance when using R134a. All of the new accumulators I've seen sold can be used with either R134a or R12 so finding one shouldn't be an issue; they also are not expensive. Also make sure you use oil that is compatible with R134a if you make the conversion (Ester or PAG). I use Ester in all of my conversions because it is compatible with R12-to-R134a conversions. PAG really isn't and PAG oil also has an issue with forming an acid if it gets contaminated with or exposed to moisture which can eat lines and compressor seals. Make sure the system is properly evacuated before charging with the recommended amount of refrigerant. Some say if you are using R-134a in an R12 system, only charge with 90% the amount of what the recommended amount of R12 is. I charged mine with the full 2.5 lbs recommended for the Fiero (using R134a).

My A/C system in my Fiero is charged with R134a and I am running a variable oriface valve. I am running a R-134a compressor also. My system blows out 30 deg air from the ducts on an 80 deg day, a few deg warmer on hotter days (usually 33-36 deg on 90 deg days as verified by a thermometer). But I've 'tuned' it to do that since the compressor I'm running still uses the cycling clutch system. Most compressors you find on 3800 engines are variable displacement types which are constant run, so you won't be able to tune them to run the system colder. Still, given that, every variable displacement R134a compressor I've installed in a Fiero using R134a refrigerant has always produced mid to high 30 deg vent temps on 80+ deg days. They cool plenty good enough for a Fiero which is usually better cooling you would find even in new cars.

-ryan

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7+ years on this same swap -- NO engine or transmission failures...

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

[This message has been edited by Darth Fiero (edited 08-18-2010).]

Thanks for the info, I was actually going to do a conversion till the ac guy told me that whole leaking to cooling stat, I bought new compressor accumulator and orifice tube, and the new compressor takes the PAG 150 i believe 2-3oz and then 5-6oz in the accumulator, I guess ill just put all the new parts on and take it to a shop to have them charge it with 134 like originally planned, thanks for the info

One thing to keep in mind -- PAG oil is sensitive to residue from R12 and mineral oil, ester oil is more forgiving and does not mind some leftover mineral oil. If you use PAG, be sure to flush the system out. (This is what I would recommend to do it correctly, as HR6 compressors used in the Fiero are designed for PAG oil and not Ester). That said, I used Ester before I knew of this and the system has worked well for the past few months, since i put it in.

How about a part number and source for the variable orifice tube??

Thanks.

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85 Fiero 4 cyl
85 Fiero 2M6D (4.3l V6 Diesel w/ 3 speed auto)
88 Coupe 4 cyl (Going to Turbo Diesel and 4 sp auto)

http://members.tripod.com/~...sel/dieselfiero.html

No P/N but Napa carries it, if you call them they should know what you're talking about...

quote Originally posted by masospaghetti: No P/N but Napa carries it, if you call them they should know what you're talking about...

I just completed two complete retrofits and used Napa parts exclusivley (we have one here at work and I get a discount ) Here are the P/N's you'll need for a complete retrofit. All prices are rounded up to the nearest dollar and come from the Napaonline website

Conversion kit (includes all orings, oil, and adapters) Napa TEM 409995 $52.00
R134 compatible reciever drier TEM 208543 $27.00
R134 pressure switch r12 works at a different pressure and this switch changes it to make it more efficient TEM 207883 $20.00
Adjustable oriface tube TEM 207325 $34.00

Or if you want a non adjusting r134 compatible oriface tube TEM 207311 $3.00

To do the conversion completly you really should (if you have the tools an know how) replace the compressor seal to the r134 compatible one. On one of the conversions I did, I forgot to bring the clutch remover and had to run it with the original seal. So far so good, but it's a good idea to change it if you can. GM P/N 2724954 around $25.00 (lost the reciept)

The correct charge I found to work effectivley was 36oz of refrigerant, just slightly over 2lbs

Hope this helps anyone else wanting to do this, someday I may make a post showing a step by step....-Jason

quote Originally posted by masospaghetti: One thing to keep in mind -- PAG oil is sensitive to residue from R12 and mineral oil, ester oil is more forgiving and does not mind some leftover mineral oil. If you use PAG, be sure to flush the system out. (This is what I would recommend to do it correctly, as HR6 compressors used in the Fiero are designed for PAG oil and not Ester). That said, I used Ester before I knew of this and the system has worked well for the past few months, since i put it in.

Well the company that I bought the new compressor from said that it takes PAG not Ester so I wont be able to use ester in the new compressor is the way I understood it, and Idk how to flush the system I'm just putting the new parts on and having a shop do the recharge so idk how I'm going to be able to do a flush

I prefer R12. Ive had many cars with both and the R12 just seems to get COLD where the 134 is just cool. The Magnum just made a very hot day bearable, but never cold. My R12 cars will keep a soda cold just setting in front of a dash vent. The only downside is the 12 is very expensive now and you can get the 134 for less than $10 at KMart. I swapped one of my Corvettes over to 134 at an AC shop and never was satisfied with the performance compared to the original after I had to replace the compressor. Fortunately for me, I really dont use AC much, prefer window down cruising.

Yea the R12 is gonna cost me about 60bucks more then a 134 charge, but the majority keeps sayin to convert to the 134 so idk, I bought all the parts and they've been sittin in my garage since tuesday, Im too lazy to go out in the heat and actually mess with trying to take the compressor off

If using r-12 is only $60 more than 134a and you can get the system to work for several years then why not? r-12 definitely works better, everyone would agree. I have not looked at the difference between the two price wise but I do know that I cannot get any r-12 related parts or freon without certification to handle r-12. With 134a I can get it and parts for it at the local auto parts stores. My car cools well enough that I have no complaints with 134a but I do miss that extra icy air that r-12 provided.

Charlie

Word of advice:

If your A/C system is currently charged with any refrigerant (especially R12), it must be reclaimed per EPA regulations. Simply venting automotive refrigerants to the atmosphere is a violation of Federal law and carries stiff penalties if you are found guilty. Some A/C shops will reclaim the refrigerant in your system for little or nothing (free), so ask around. Others may only charge a moderate fee but it shouldn't be too expensive. I certainly don't recommend anyone go out and just open their systems and vent them to the atmosphere.

If you are mechanically inclined but have little experience with Air Conditioning systems, you can probably do the part swapping work yourself if you have a GM service manual. But in order to evacuate the system, you will need an A/C system vacuum pump and an A/C manifold gauge set. Charging can be done by using the disposable cans which come in 12oz sizes; so installing a total of 36oz of R-134a (2.25lbs, which is 90% of the rated 2.5lbs capacity) will not be difficult. The oil should be added to the components of the system before reassembly as explained in the service manual (it will tell you the amount of oil to add to each component). If you can't get a manifold gauge set and a vacuum pump for this job, you can do the parts swap yourself but you would need to take the car to a shop to have the evacuation and charging done. DO NOT charge a system that has not been evacuated (pulled down to a vacuum). Doing so can result in compressor and system damage, as well as poor system performance.

If you are not very mechanically inclined and/or have trouble following the instructions in a service manual, I strongly recommend you let a shop do this work for you. This is not meant to be a rude comment against anyone, but rather: a warning. If you don't know what you are doing here, you could easily damage something and end up costing yourself a lot more money to get it fixed and working vs. just having a shop do the entire job in the first place. I certainly don't recommend anyone attempt to do even a parts replacement without a shop manual.

[This message has been edited by Darth Fiero (edited 08-20-2010).]

quote Originally posted by cptsnoopy: If using r-12 is only $60 more than 134a and you can get the system to work for several years then why not? r-12 definitely works better, everyone would agree. I have not looked at the difference between the two price wise but I do know that I cannot get any r-12 related parts or freon without certification to handle r-12. With 134a I can get it and parts for it at the local auto parts stores. My car cools well enough that I have no complaints with 134a but I do miss that extra icy air that r-12 provided. Charlie

Yea a local shop told me to do a full recharge with 134 its 19.99 a pound and the R12 is 39.99 a pound so in the end its only 40-60 more to do a R12 but either way I should still change my current parts right? The compressor accumulator and orifice tube, even if I do a R12 cuz i cant just do a recharge on the old system since it hasnt been cold in years right?

quote Originally posted by White88Formula: Well the company that I bought the new compressor from said that it takes PAG not Ester so I wont be able to use ester in the new compressor is the way I understood it, and Idk how to flush the system I'm just putting the new parts on and having a shop do the recharge so idk how I'm going to be able to do a flush

The reason for using Ester is that PAG oil requires a 100% perfectly clean system to work properly. If you flush with solvents to get it this clean, your hoses will fail as they need the inside barrrier coat of oil to remain leak free. Also if there is any trace of old mineral oil in there PAG will fail you and if you cleaned everything you're still in trouble. I just blow the lines clean and leave them at that. I am running Ester oil with a compressor from a 2006 GTP and two years later everything still cools so good it will blow you our of there on high. Don't forget to change the accumulator when you do the conversion and put new O rings at the fittings. Properly done and charged you can get an R-134A system to blow very cold.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Personally, I think the R-12 vs. R-134a debate regarding Fieros is not a big deal. The Fiero AC system is not like most other cars AC system. You have a fairly large condenser in the Fiero that is able to shed heat much more efficiently because it doesn't share a space with an engine. Secondly, the system holds a lot more freon than most other cars and all of the freon lines are away from the engine heat which also helps. And the evaporator is not up against a hot firewall either. My son's 88 Formula has R-134a from the previous owner and when I drive it i have to turn it down it's so cold. I can understand what Roger said about his Vette working better with R-12 but that car has a relatively cramped engine compartment and all the AC components are located within 2 feet of the engine.

quote Originally posted by White88Formula: Yea a local shop told me to do a full recharge with 134 its 19.99 a pound and the R12 is 39.99 a pound so in the end its only 40-60 more to do a R12 but either way I should still change my current parts right? The compressor accumulator and orifice tube, even if I do a R12 cuz i cant just do a recharge on the old system since it hasnt been cold in years right?

Correct, those parts should be replace at minimum. The Fiero R12 charge is 2.5 lbs ($100 at their rate) or ~2 lbs R-134a ($40). The shop should be able to pull a vacuum on the system and check for leaks that way when they fill it.

Im hoping those rates for 134 are with labor included. I just bought some 134 for a dealers car at Walmart for $6 a pound.

quote Originally posted by Dennis LaGrua: The reason for using Ester is that PAG oil requires a 100% perfectly clean system to work properly

Well If the compressor company told me to use PAG how can i run ester in it? wont that screw something up or at minimum ruin my 2 year warranty that came with the compressor since Im not running the correct oil?

quote Originally posted by White88Formula: Well If the compressor company told me to use PAG how can i run ester in it? wont that screw something up or at minimum ruin my 2 year warranty that came with the compressor since Im not running the correct oil?

Oil = lubrication. I hear what you are saying but Ester oil is still A/C oil. Its a concersion/retofit oil used in redone systems. My 2006 GTP compressor that was designed for PAG is working fine on Ester two years after the fact. Fiero compressors designed for 535 mineral A/C oil work fine with it too. Will ester oil work in a compressor designed for PAG? I would say that my expereince seems to indicate that it will.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: Oil = lubrication. I hear what you are saying but Ester oil is still A/C oil. Its a concersion/retofit oil used in redone systems. My 2006 GTP compressor that was designed for PAG is working fine on Ester two years after the fact. Fiero compressors designed for 535 mineral A/C oil work fine with it too. Will ester oil work in a compressor designed for PAG? I would say that my expereince seems to indicate that it will.

I would use it except for the fact that I dont want to void the warranty especially since the compressor was about $250