My AC evaporator started to leak and I just had it replaced, along with the dryer, at Sterling McCall Acura in Houston. My wallet is now $2150 lighter. I requested a change-over to R134a as part of the service but they recommended not doing so because the aging system on my '91 would not handle the increased pressure involved, nor would the system blow as cold. I followed their recommendation, even though I have never heard of that warning. Has anyone else?
R134a not recommended?
- Thread starter Oldguy
- Start date
I don't know about the presure but it's true 134a does not cool as well as R12. Lots of NSX's have been converted to 134a but when I had my AC serviced last year at the Acura dealer they recharged with R12 and did not offer a R134a conversion.
If I'm recalling it right, when retrofitting to R134a you need to put 50 grams less than the R12 pressure.
I've never heard that before. Lots of NSXers have done the conversion with no ill effects reported.Oldguy said:
R-134a is no less effective than R12 as far as refrigerants go.
However, a converted R12-to-R134a system will not be as effective as a system that is originally R134a. The best you can do is evacuate the R12 system as best you can (including the lubricating oils) then convert all the seals/connectors/etc. and the system will work WELL (but perhaps not as well as the original R12 system). It's up to you if you decide to convert to R134a later on, or if you want to stick to the R12 system.
Keep in mind ~ R12 is increasingly rare and is also extremely expensive to service. Often, a conversion to R134a is cheaper than a full R12 service. A R134a system in general will be cheaper to deal with. There's also the whole environmental aspect (if you happen to care).
However, a converted R12-to-R134a system will not be as effective as a system that is originally R134a. The best you can do is evacuate the R12 system as best you can (including the lubricating oils) then convert all the seals/connectors/etc. and the system will work WELL (but perhaps not as well as the original R12 system). It's up to you if you decide to convert to R134a later on, or if you want to stick to the R12 system.
Keep in mind ~ R12 is increasingly rare and is also extremely expensive to service. Often, a conversion to R134a is cheaper than a full R12 service. A R134a system in general will be cheaper to deal with. There's also the whole environmental aspect (if you happen to care).
also keep in mind there are now drop in replacements for R-12 that ARE environment friendly, cool better than R-12, and requires no conversion whatsoever. Search this forum for the details, I've posted them two or three times in the past month. The R12 to R134a conversion topic seems to be one of the most popular new threads.... where's the forum nazi on this one?!? 
The original issue here is that an Acura dealership (well versed in the NSX, by the way) has recommended against a conversion. Since they are losing income with such a stance, I'm assuming that they must have some compelling reasons. The question remains: Is this common advise among Acura dealerships.
Conversion v factory 134a
may be an issue--I do not know the history of my 93 but was told by Basch Acura that my car has the "factory 134a" and not the conversion.. Sounds like prior owner may have gotten the AC from a newer vehicle and swapped it out of my 93 because the 93's did not come with the 134a refrigerant....THAT may be the way to go--find someone willing to sell the AC components from a vehicle after 95...
OOPs --NSXTASY advised only 91 & 92 come with the R12--shop misinformed me--they thought it was 95 and newer....
may be an issue--I do not know the history of my 93 but was told by Basch Acura that my car has the "factory 134a" and not the conversion.. Sounds like prior owner may have gotten the AC from a newer vehicle and swapped it out of my 93 because the 93's did not come with the 134a refrigerant....THAT may be the way to go--find someone willing to sell the AC components from a vehicle after 95...
OOPs --NSXTASY advised only 91 & 92 come with the R12--shop misinformed me--they thought it was 95 and newer....
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R134 does run at higher pressures and the heat absorbtion is less therefore it cools a bit less, although almost impossibe to tell the difference unless you have a digital thermometer stuck in the vents at all time., There is a direct replacement the we use on low and mid temperature systems, that seems to work perfectly in auto air conditioning, it goes by the name "HOT SHOT"
Armando
Armando
I just had my 92 converted to R134a w/o issue. Pressurization was fine as well. Have them also put in the luminescent dye to facilitate locating a leak in the system w/ a blue light.
Jeff
Jeff
No, that's not what happened.jrehner said:
All NSXs sold for model year 1993 and later come from the factory with an R-134a system. Only the 1991-92 NSX came with R-12.
robr said:also keep in mind there are now drop in replacements for R-12 that ARE environment friendly, cool better than R-12, and requires no conversion whatsoever. Search this forum for the details, I've posted them two or three times in the past month. The R12 to R134a conversion topic seems to be one of the most popular new threads.... where's the forum nazi on this one?!?
OK, now you've peaked my interest. What are you referring to?
this is from an email mark basch sent me back in 2000
--------------------
I offer all my customers- NSX to Civic, the
Freeze 12 option when doing a repair or recharge. I buy it in 30 lb cylinders for about 150. I sell it for 7.00 a pound, so its more like one fifth the price PLUS you only use 78 % Freeze 12 as the systems R12 capacity. It uses less because its compressability is so much greater, that it expands into a slightly larger space. (not sure I explained THAT correctly!) I've used it in about 200 customer cars this summer, plus my NSX, and the fully custom built a/c in Dali's Candy Cane 3.2 conversion racer I've been building this summer as well. Not a single prolem and the vent temps are 3 or 4 degrees cooler.
Stay Kool,
Mark
--------------------
I offer all my customers- NSX to Civic, the
Freeze 12 option when doing a repair or recharge. I buy it in 30 lb cylinders for about 150. I sell it for 7.00 a pound, so its more like one fifth the price PLUS you only use 78 % Freeze 12 as the systems R12 capacity. It uses less because its compressability is so much greater, that it expands into a slightly larger space. (not sure I explained THAT correctly!) I've used it in about 200 customer cars this summer, plus my NSX, and the fully custom built a/c in Dali's Candy Cane 3.2 conversion racer I've been building this summer as well. Not a single prolem and the vent temps are 3 or 4 degrees cooler.
Stay Kool,
Mark
Another question: What are the negative consequences of running 134A into a system that currently has or is low on freon? I have never "flushed the system" and still have not encountered any system problems. I have done and seen this done to many vehicles over the past few years. As of yet I have seen no problems. Using plenty of sealer and oil followed by the 134A seems to hold up. But is there something I have not been told or am supposed to believe is negative about doing it this way?
R-134a is not compatible with the 30W mineral oil used with R-12 systems. It must be thoroughly flushed and cleaned from the system. This cannot be emphasized enough. It is a difficult task. Either PAG (polyalkylene glycol) synthetic or AB (alkaloid benzyne) oils used with R-134a react violently with the chlorine residues from the R-12 oils. Premature compressor failure typically results.Juice said:
Auto air conditioning conversion must also involve changing the seals on all hose fittings, front compressor seal, and in general, any rubber piece that the R-134a will contact. The hoses must also be changed, or they will begin to leak.
Oldguy said:
I have heard of a similar warning (ie. keep it R12) by the instructor in my automechanics class.
Well I picked up a R134A conversion kit from my local Auto Zone just so I could see the instructions included in the kit. The only information provided about conversion is that the freon is to be removed into an aproved container by an authorized facility. No mention is made of flushing the system, changing hoses or gaskets, premature compressor failure, or oil incompatibility.
This has me a bit perturbed. R124a is readily available and there is no outstanding indicator of the damage it suposedly can do. I have never seen any of this damage first hand but I have heard over and over that it can be serious. But on the other hand, Freeze12 requires a license to buy and I have never heard of it up until 2 days ago. It seems to be the magical solution to a pre 98(?) AC unit recharge, but has never been suggested to me by a professional in the field. Doesn't this seem to be a little out of whack?
This has me a bit perturbed. R124a is readily available and there is no outstanding indicator of the damage it suposedly can do. I have never seen any of this damage first hand but I have heard over and over that it can be serious. But on the other hand, Freeze12 requires a license to buy and I have never heard of it up until 2 days ago. It seems to be the magical solution to a pre 98(?) AC unit recharge, but has never been suggested to me by a professional in the field. Doesn't this seem to be a little out of whack?
Just call Mark Basch if you have questions on it, there isn't anyone more professional in the US when it comes to working on the NSX.
True.
