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r12 system w/freeze 12 & 134 oil?!

rtbme on Mon August 06, 2012 5:34 PM User is offline

Year: 1964
Make: Chevrolet
Model: Impala
Engine Size: 327
Refrigerant Type: R12 & Freeze 12
Country of Origin: United States

I've had the 64 Impala for 18 yrs. In that time i've added R12 perhaps 3 times due to high temp out the vents (58-60 degree).
This would lower the output and be fine for a few seasons of use. I'd be around 50-52 degree I don't think I've ever been much lower than that.
2 or 3 years ago i had a shop add what I thought was R12. I was back today because of high output again (60) and the cooling comes and goes.
Turns out what was put in was freeze 12 last time. So we added one 12 oz can then another. We we're seeing air in the reciever/dryer window.
The compressor was making some noise lately so the fella thought he'd add some oil.
I can around the front of the car and i see he's adding 134 oil.
The system is not blowing any cooler now and after reading here i think I may be in trouble with what's been put in the system.
I do know when he added the freeze 12 the low side was reading around 90 psi but once the can emptied it was at 40psi.
Do I now have to find a shop to evacuate and start all over? Is this 134 oil going to cause big problems?
Thanks for any information

TRB on Mon August 06, 2012 8:17 PM User is offlineView users profile

Good luck finding a "professional" shop will to reclaim the contaminated refrigerant. Best to contact a Freeze12 distributor and see what they have for this kind of situation. As far as I'm concerned. Total system flush and new drier, oil and refrigerant for starters.


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rtbme on Mon August 06, 2012 9:48 PM User is offline

is the contamination the R12/ freeze-12 mix or the 134 oil.
not that it matters much. To use the term "reclaim" may be a little generous here.
not sure recycle fits either. how about "dispose of properly"
so is the mixture in the system going to wipe out the compressor?
should i be removing the belt?

TRB on Mon August 06, 2012 10:58 PM User is offlineView users profile

Mixed refrigerants is prohibited by law. That is where your issue is in my opinion. As for how well it works or what it will do to the system. I personally do not know as I never mix refrigerants.


When considering your next auto A/C purchase, please consider the site that supports you:

newton5 on Mon August 06, 2012 11:21 PM User is offlineView users profile

Your main problem is that you have 2 (actually 3)different refrigerants mixed in your system. Unless a shop has a "trash" recovery unit, they have no way to recover it without contaminating their recycled stock. Many shops don't have such a unit because it is another piece of equipment($$) and it costs them to get rid of the "trash" refrigerant.($$). It's easier and cheaper for them to send you elsewhere.
Even if your shop removed the R12 before using the Freeze 12, it can't be recovered and then recycled. Being a blend, it is recovered as "trash".
You can try calling some reputable shops in your area and asking if they can handle mixed or contaminated refrigerant. I have a dedicated recovery machine that I use for just such cases as yours, fortunately it doesn't cost me much to have it legally disposed of.
The oil is a lubrication problem, but that can be remedied by flushing the system. Mixing 2 different type oils is asking for problems, just like in an engine. Disposal isn't really an issue.

As Tim said; Recover, system flush, reseal, new receiver/dryer, evacuate and recharge with R12 at minimum. It's not as bad as it sounds. That's pretty standard to repair a 48 year old AC system and make it reliable. If the compressor is noisy you should replace it. Check out the Pro6Ten compressor as an option.

As you found out there are,sadly, many shops that "do AC" but really don't know what they are doing. Adding oil to your 64, for instance, requires removing the compressor to add oil to the sump. It sounds like your shop was adding it right into the service fittings, as on newer vehicles.

When looking for a shop to properly service the AC in your 64, make sure they are familiar with the GM STV (suction throttling valve) system and the A6 compressor. It's a very good system, but it was phased out before many of the guys who work on AC systems today were born. Finding a shop that "knows" your system can be tricky.

Good Luck

Edit: No need to remove the belt, just unplug the 2 wire connector from the AC clutch and secure it out of harms way until you can have the system checked or repaired.

Edited: Mon August 06, 2012 at 11:43 PM by newton5

rtbme on Tue August 07, 2012 8:50 AM User is offline

Great reply, thank you. I'll do as you suggested.
while this is going on should i be converting to 134?
Is this just an O ring swap & use of propper oil?

Leggie on Thu August 09, 2012 3:30 AM User is offline

Name and location of said hack shop?

Below only applies if you're in USA or Canada. Disregard otherwise.

I would take it back to them and demand that they pull the contaminated refrigerant. If they recover it into their 134a or 12, they're the one who suffers economic loss. If they vent it, report them to EPA or the Canadian equivalent. Hacks shouldn't be allowed to remain in business.

Back when R12 restriction first kicked in, public as well internal fleet shops were fined by the EPA for using hydrocarbon refrigerant like
Super-Freeze 12 and Enviro-Safe 12.

powerflite on Thu August 09, 2012 1:56 PM User is offline

I believe Freeze 12 is EPA approved.l

NickD on Thu August 09, 2012 3:50 PM User is offline

Screw what the EPA approves or disapproves, has nothing to do with proper performance or reliability, just whatever they feel if released, will harm not the environment.

Worse thing about Freeze 12, its not a homogeneous refrigerant but a blend of EPA refrigerants, if the lighter of the two refrigerants leaks out and will because it is lighter, you just lost your so-called oil carrier in the case of Freeze 12. Most of it is R-134a anyway and the rest of the system had to be converted to R-134a compatibility.

Worthless, might as well have just converted to R-134a, but if a POA system, would have other problems. If you paid for R-12, speaking of screwing, you really got screwed.

TRB on Thu August 09, 2012 3:56 PM User is offlineView users profile

Freeze 12 is 80% R134a to begin with. If the drier was not replaced to a R134a compatible model. Get ready for a ruptured Desiccant bag and a costly repair.


When considering your next auto A/C purchase, please consider the site that supports you:

newton5 on Thu August 09, 2012 11:09 PM User is offlineView users profile

On your 64, it would be best to stay with R12.
However, it can be made to perform pretty well with R134a. You would need to have the Suction Throttling Valve adjusted to maintain a slightly lower evaporator pressure, 26-28psi if I recall correctly. If you search the forum for R134a conversion on POA systems, the same info will apply.
You would also need to make sure your cooling system is 100% and to maximize airflow over the condenser. The old tube and fin condenser is the limiting factor when converting to R134a.
Depending on how involved you want to get, a parallel flow condenser is a very good investment when converting those old systems to R134a.
Hope this helps.

mk378 on Fri August 10, 2012 12:26 AM User is offline

The original R-134a based Freeze-12 has no advantage over straight R-134a other than that you don't have to change the oil. Beware that people are now selling HC refrigerants under all sorts of names that end in 12. Mixtures of R-12 with R-134a have worse performance than either one alone. You have to get rid of that mixture and decide what to use.

TRB has a good point that if your drier is original, or one from before the introduction of 134a compatible types, it would have been ruined by the 134a. Also when PAG oil meets even a small amount of R-12, it turns to sludge. The other type of 134a compatible oil, ester or POE, is OK with R-12.

Edited: Fri August 10, 2012 at 12:27 AM by mk378

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