134a Conversion
- Thread starter pnamarble
- Start date
There is Freeze 12, but its slightly tough to buy for the average hot rodder since it seems they have placed controls on almost all of the R12 stuff, including replacements. For a real R134a conversion you need to replace the dryer, since it will hold incompatable oil, O-rings, since they might not be compatable, POA valve, so you have the correct pressure drop to properly cool, fittings so that the correct lines for R134a will screw on (think leaded gasoline nozzles and you'll get the idea why they are different), and its best to replace the compressor so it builds the correct highside pressure since R134a take a larger pressure drop to extract as much energy though the throttling process. Hopefully SavannahAutoAir chimes in, he's the HVAC expert, I just did some of these in High School then took Thermodynamics in college to understand what's going on and why you need to change stuff.
Hope this helps,
Hope this helps,
I just did the conversion on my 86 T-type...
Bought 4 cans of R134a @ $12.99ea, and a R134a oil charge/conversion kit for $19.99 at Autozone.
Borrowed a buddy's vac pump & guages, sucked it down for 1.5 hours @ 30hg. This (so I'm told) will boil the oil and any moisture from the system. I started the engine, put the oil charge in, jumped the plug at the rec/drier to kick on the compressor, and started putting freon in...It started getting cold after the 2nd can.
I'm told that you should only fill R134a to 85% of the systems R12 capacity. I think we calculated it to be 44.2 oz of 134a. It's far from an exact science when using the little pounder cans, so I "guesstimated" and put just a tad under 4 full cans in it. (4 cans = 48 oz. @ 12oz ea.)
The AC blows ice cold and cycles perfectly.
I couldn't be more happy, and I managed to do it myself.
I even did a conversion on another friend's '89 Saleen a few days later, and was 100% successful.
Bought 4 cans of R134a @ $12.99ea, and a R134a oil charge/conversion kit for $19.99 at Autozone.
Borrowed a buddy's vac pump & guages, sucked it down for 1.5 hours @ 30hg. This (so I'm told) will boil the oil and any moisture from the system. I started the engine, put the oil charge in, jumped the plug at the rec/drier to kick on the compressor, and started putting freon in...It started getting cold after the 2nd can.
I'm told that you should only fill R134a to 85% of the systems R12 capacity. I think we calculated it to be 44.2 oz of 134a. It's far from an exact science when using the little pounder cans, so I "guesstimated" and put just a tad under 4 full cans in it. (4 cans = 48 oz. @ 12oz ea.)
The AC blows ice cold and cycles perfectly.
I couldn't be more happy, and I managed to do it myself.
I even did a conversion on another friend's '89 Saleen a few days later, and was 100% successful.
Refrigeration oil will not boil and evaporate under a deep vacuum and it also will not sucked out by the vacuum pump.
I think what 84GNGary meant was that the oil for R-12 is not compatible with R-134a and should be removed prior to refilling the system with R-134a and the correct refrigerant oil.
The vacuum pump lowers the atmospheric pressure above the oil so whatever moisture is in the oil will be removed since
water + R-12 = corrosion.
I think what 84GNGary meant was that the oil for R-12 is not compatible with R-134a and should be removed prior to refilling the system with R-134a and the correct refrigerant oil.
The vacuum pump lowers the atmospheric pressure above the oil so whatever moisture is in the oil will be removed since
water + R-12 = corrosion.
You are correct GN Owner, R 12 uses mineral oil and 134a uses a synthetic oil. The two oils will not mix with each other or mix with the other type of refrigerant. The oil that leaves the compressor travels through the system with the refrigerant and returns to the compressor. If the oil does not mix properly with the refrigerant it will leave the compressor and not return. It will just stay out in the system somewhere . This will eventually lead to compressor failure.
What I was taught to ensure proper compressor lubrication after a retrofit you should have less than 2% of mineral oil remaining in the system. The only way to do this is by testing,draining, flushing and changing the oil until you are below 2%. This process is very impartical on an automotive A/C system.
I don't know or care what they are selling or telling you at your local auto store as far as changing your system over to 134a. I do know that I will never put it in my car.
What I was taught to ensure proper compressor lubrication after a retrofit you should have less than 2% of mineral oil remaining in the system. The only way to do this is by testing,draining, flushing and changing the oil until you are below 2%. This process is very impartical on an automotive A/C system.
I don't know or care what they are selling or telling you at your local auto store as far as changing your system over to 134a. I do know that I will never put it in my car.
Red Regal T
Senior Member
- Joined
- May 24, 2001
Buy a nipple for your drier and a hose to install the 134A and put it in.
Vaccuum it down for at least 45 minutes, use ester oil and forget about it.
I have completed countless conversions on all makes and have only ever lost two compressors and both were old fords. Just did two fords, a dodge truck and a chevy this week.
You can go through, spend all the money to do it right, new compressor, condensor, o rings, certain hoses, accumulator, orifice tube, etc. Or, you can try it the cheap way and see if it works good enough for you. Chances are, you will be happy.
If you do blow the compressor, then you are not out anything but freon and oil.
Good luck,
Vic
I have completed countless conversions on all makes and have only ever lost two compressors and both were old fords. Just did two fords, a dodge truck and a chevy this week.
You can go through, spend all the money to do it right, new compressor, condensor, o rings, certain hoses, accumulator, orifice tube, etc. Or, you can try it the cheap way and see if it works good enough for you. Chances are, you will be happy.
If you do blow the compressor, then you are not out anything but freon and oil.
Good luck,
Vic
rodman99999
Active Member
- Joined
- Mar 25, 2004
So for $6.00 a pound on eBay: How can you go wrong trying the Freeze 12? Nothing else to change, or worry about(providing you have no leaks anywhere)!!
Harry Mash
"Turbofan"
- Joined
- May 3, 2004
In the early 90s, using GM service bullitin #431207a- I evacuated the air system, put a vacuum on it for a while--- added R134 and pag oil and it works fine--- for lo these many years. Good luck with yours.
Harry
Harry
Spoke with a local rodder last night, trying to line someone up to charge my AC. He told me that he has been using 134 in his GM truck and Firebird for the past 4 years----and it blows nice and cold. He just bought the adapter for the 134 and put it straight in to his R12 systems w/o changing a thing. No problems. I'll be the first to admit, that I don't know diddly about AC, but I do know his car is alot colder riding in. Think I'll guinea pig the van first. Brian
ITSAV6
It's my Granny's car!
- Joined
- Nov 13, 2001
freeze 12
Freeze12 is 80% R134A and 20% R142B. The latter is for oil circulation. R142B will bleed out of a leak before R134A leaving you with a system that has... R134A and no way to circulate the oil leading to compressor death. No compressor manufacturers at this time warranty their units with anything but R12 and R134A. If you do have a problem with Freeze12 and want other help, you are on your own for no shop will touch it.
http://www.aircondition.com/wwwboar...sages/3484.html
http://www.aircondition.com/wwwboard/2003Q1/4682.html
Freeze12 is 80% R134A and 20% R142B. The latter is for oil circulation. R142B will bleed out of a leak before R134A leaving you with a system that has... R134A and no way to circulate the oil leading to compressor death. No compressor manufacturers at this time warranty their units with anything but R12 and R134A. If you do have a problem with Freeze12 and want other help, you are on your own for no shop will touch it.
http://www.aircondition.com/wwwboar...sages/3484.html
http://www.aircondition.com/wwwboard/2003Q1/4682.html
rodman99999
Active Member
- Joined
- Mar 25, 2004
So who's going to warranty the compressor that's been on my car since '87 anyway? All mine needs is perhaps a 1/2 lb (the pressure switch is cycling the compressor on and off). Plenty of freon in there to circulate the oil. I have(in the past) topped off systems that contained the greater part of their R12 charge with a touch of 134a without any problems. The thought of using a component designed(supposedly) to work for the purpose(Freeze 12) doesn't bother me in the least. If I were needing a full charge, I'd do it (after finding out where the old charge went, and draining the old oil) with the "ester" oil, Freeze 12, and see how long it lasted. Total expenditure: $25.00 and how ever long it took to drain the oil/ fix the leak/ evacuate the system/ recharge.
