I've been using Duracool for a while now and I'm very happy with it.

R134a runs perfectly well in a 924s, 944 or 968.

I am not promoting or defending the alternative refrigerant you have mentioned, however the facts are
R134a is more common as compared to other refrigerants (whether EPA approved or not approved) and is therefore more readily "serviceable".

From the EPA regs: <i>Under the SNAP rule, each new refrigerant must be used in accordance with the conditions listed below. If you choose to use an alternative, make sure the service shop meets these requirements and that it <b>has dedicated recovery equipment for blends... </b> </i> For the average repair shop having "dedicated equipment for each type refrigerant" is a very very expensive investment to satisfy the wants of a few car owners.

<b>Misleading Use of "Drop-in" to Describe Refrigerants</b>

<i>Many companies use the term "drop-in" to mean that a substitute refrigerant will perform identically to CFC-12, that no modifications need to be made to the system, and that the alternative can be used alone or mixed with CFC-12. However, EPA believes the term confuses and obscures several important regulatory and technical points. First, charging one refrigerant into a system before extracting the old refrigerant is a violation of the SNAP use conditions and is, therefore, illegal. Second, certain components may be required by law, such as hoses and compressor shutoff switches. If these components are not present, they must be installed. See the section below on use conditions for more information on these points. Third, it is impossible to test a refrigerant in the thousands of air conditioning systems in existence to demonstrate identical performance. In addition, system performance is strongly affected by outside temperature, humidity, driving conditions, etc., and it is impossible to ensure equal performance under all of these conditions. Finally, it is very difficult to demonstrate that system components will last as long as they would have if CFC-12 were used. For all of these reasons, EPA does not use the term "drop-in" to describe any alternative refrigerant. </i>

<b>UNIQUE FITTINGS:</b>
<i>
Each new refrigerant must be used with a unique set of fittings to prevent the accidental mixing of different refrigerants. These fittings are attachment points on the car itself, on all recovery and recycling equipment, on can taps and other charging equipment, and on all refrigerant containers. If the car is being retrofitted, any service fittings not converted to the new refrigerant must be permanently disabled. Unique fittings help protect the consumer by ensuring that only one type of refrigerant is used in each car. They also help protect the purity of the recycled supply of CFC-12, which means it will last longer, so fewer retrofits will be necessary nationwide. The list of fittings is available in an EPA fact sheet titled "Fitting Sizes and Label Colors for Motor Vehicle Refrigerants." <i>

<b>LABELS:</b>
<i>Whether a car is originally designed to use a new refrigerant or is retrofitted, the technician must apply a detailed label giving specific information about the alternative. The label's background color is chosen by the manufacturer to be unique, and the label colors for each refrigerant are listed in an EPA fact sheet titled "Fitting Sizes and Label Colors for Motor Vehicle Refrigerants." The label shows:

* the name and address of the technician and the company performing the retrofit;
* the date of the retrofit;
* the trade name, charge amount, and, when applicable, the ASHRAE numerical designation of the refrigerant;
* the type, manufacturer, and amount of lubricant used; and
* if the refrigerant is or contains an ozone-depleting substance, the phrase "ozone depleter"

This label covers up information about the old refrigerant, and provides valuable details on the alternative and how it was used. It also tells the owner who performed the retrofit. </i>

<b>Complete Details about EPA Regulations regarding Alternative Refrigerants can
be found here:</b>
http://www.epa.gov/ozone/snap/refrigerants/hc-12a.html#qdura

Been using Duracool in one car since 1995 and the 944 since 1997. Works well in both.

Simply put, 134 will work in most any r12 system (provided that it is proper working condition) after removing most of the old mineral oil and replacing with the oil that comes with most 134 conversion kits. 134 may leak out slightly quicker than r12 due to molecule size, but adding a can of 134 on occasion is simple and cheap.

Some will argue that 134 does not cool as well as r12, but it will probably work good enough in most applications.

While the hoses that came in r12 equipped cars in theory should not be able to retain 134, they actually do an acceptable job as the mineral oil in r12 systems over the years soaks into the hose liner which in turn helps the hose retain 134 adequately.

I converted my 911SC last summer to 134 and it has very long hoses compared to most cars. Some folks claimed that all the hoses should be replaced, but after fixing some leaks, adding proper 134 oil, changing the drier, evacuating the system then charging with 134, my system worked fine all summer and fall without requiring any more refridgerant. This spring I may have (or may not have) to add a can, we will see.

I started this looking for some good information and each of you have definitely provided a lot and several options. Here is my delimma...The car has 100,000 miles on it give or take a few and I'm not sure where the compressor is in terms of life....may have already been replaced, I don't know. My 86 went out at about 120,000 I think, so that's the only gauge I have to go by at the moment when I say the compressor may be near end of life. That doesn't bother me too much and I am certainly open to a new compressor if need be, but I am also going to at some point pull the dash to resurface it. Since the expansion valve in under the dash (so I'm told)...while I have the dash out might just be a good time to replace the expansion valve and compressor and go 134 with a new system with possibly the exceptions being the condesor and evaporator...just clean those as I shouldn't have to replace them should I? I guess one thing to consider is...was my 86 a good gauge for compressor life or do you all get more miles on your compressors than that. Of course being in Texas, January is the only month we don't run our a/c systems so they get a lot of use here. But this car came from Illinois and I have no idea how much the a/c system was run before. So, tell me what you think of this plan....I can either switch to R134 or use Duracool until the compressor croaks or I pull the dash and replace the expansion valve (whichever comes first)....then put in a whole new system as I would like ten more years from this car. While the dash is out, it seems like an opportune time to clean and replace everything giving me the longest life possible for the a/c system. The problem I had with my 86 was...at least according the guy who held a gun to my head while he replaced everything....was when the compressor blew, it distributed this black substance throughout the whole system that he couldn't get out with his flush solvent, so he had to replace everything with new. Anybody else have this problem with their original compressor? This was kind of making me lean toward replacing everything now before it contaminated all the parts in my whole system.

A quick look at the pressure/temperature curves for R-12 and R-134a should be enough to convince anyone that R-134a is clearly inferior as a refrigerant. It requires higher head pressures to provide the same cooling capacity as R-12 and even with the proper oil, it does not lubricate as well as R-12.

I've spoken with several HVAC professionals and posed the following question: "If you evacuate a system designed for R-134a and use R-12 instead, what would happen?"

The answer has UNIVERSALLY been this: "It would cool better and last longer."

In a car, you will typically see a 10-15 degree (fahrenheit) increase in vent temperature when converting from R-12 to R-134a, the head pressures in your system will run 20-40 PSI higher, and your compressor will have to work harder. In most cases, this is still within the design tolerances for the parts, but it does not negate the fact that you are working the system harder and essentially making it less reliable.

Refrigerants like Duracool actually have superior temerpature/pressure curves to R-12 and it lubricates on par with R-12. This means that for identical cooling to R-12, Duracool needs lower system pressures which extends the service life of the A/C system. I saw a 3-5 degree decrease in vent temperatures with Duracool when compared to R-12.

R-134a will do a great job in a system designed for R-134a, but in a system designed for R-12 it will be mediocre at best.

Aaron, I agree that 134 does not cool as well as r12. I was just stating that: just because it does not perform as well, in many cars, it will still provide an adequate cooling effect. Some folks are not satisfied unless the system can make them wear a sweatshirt inside the car on a 100 degree day. Others are satisfied with slightly less than optimum results.

Old 911's even when new and running r12 were known to have poor AC performance, yet unless I am sitting in a long traffic jam on a 90 degree day, mine keeps me plenty cool even with 134 (on a 90 degree day, at freeway speeds, I have to back off on the AC or my teeth will start chattering). Of course I live in Ohio where mutiple 90+ days in a row do not happen often. 944's AC systems are much better than the old 911's.

I have no problems with Duracool or others, I considered them but opted for the easy to get, inexpensive 134. Someday that may go way up in price and I will switch to something else.


Tom, if your AC compressor works fine why worry about it now? Unless you enjoy spending money, just use it until it NEEDS to be replaced.:) Heck your alternator, starter, fuel pump etc etc all will fail eventually too, but it might not be wise financially to replace all this stuff when it still has life left in it.

I use duracool in my 951, and have used it in a few friend's cars without any problems at all. Plus, it's made in edmonton, so I'm supporting a canadian company :)

You guys have a couple good points. AaronM, where do you get the duracool? How expensive is it? If I bought a case of it and kept it on the shelf, that availability of R134 wouldn't be such an issue. Maybe duracool is the way to go unless I replace the whole system. I definitely agree with you that R12 did a much better job than R134. I haven't found anyone yet that disputes that one.

Tim, to your point about using it until it breaks...definitely some logic in that, but I was worried about two things. 1. Because the expansion valve is so hard to get to, I might consider just completely rebuilding the a/c system while I was already there for the dash. In other words, I don't want to pull the dash today to fix the cracks and then in six months pull it again to replace the expansion valve because the compressor gave (lazy, huh?). I would prefer to only pull the dash one time. When a compressor goes, you really should replace the expansion valve at the same time because the compressor may have released "stuff" to clog the expansion valve and ruin a new compressor...if I understand as much as I have been told. The other part to waiting until the compressor goes is that on my 86 (again according to the repair guy that robbed me) the compressor contaminated the whole system with some black stuff that he couldn't get out causing him to replace the entire system including condensor and evaporator ie..pulling the dash again and adding more expensive parts. The reason I would want to rebuild it isn't because I just want to spend money, more that I don't want to replace everything when it goes and have to pull the dash a second time to get another 3 to 6 months use of a compressor that might be ready to go anyway. If they had only put that expansion valve in a more appropriate place the question would be simpler. With an alternator or starter, the removal and replacement is very simple, not so with a compressor because of the expansion valve. What were they thinking on that one? I guess there would still be the contamination issue. Has anyone run a compressor until it totally broke and if so, did you have any contamination issues...or did I just have a bad a/c person? Thanks for all the help everyone.

<I>A quick look at the pressure/temperature curves for R-12 and R-134a should be enough to convince anyone that R-134a is clearly inferior as a refrigerant. It requires higher head pressures to provide the same cooling capacity as R-12 and even with the proper oil, it does not lubricate as well as R-12. </i>

This is not 100% true perse. As I recall R134a has a greater propensity, pound for pound, to remove more btu's than R12, on the evaporator side. However it does run at higher head pressures. How high the pressures are depends upon the capacity or efficiency of the condenser side of the circuit. Typically up to 85F or so ambient the pressure curves or R134a and R12 are almost in line, above 85F nominal the R134a line curves upward; and depending upon who's chart you are looking at (a training manual, the refrigerant manufacturer's or an independent), the charts vary.

In terms of wear characteristics relating to oil type, mineral, ester or pag's, there are many many studies by fleet owners, the compressor manufacturers, the Mobile Air Conditioning Society and more who have different findings in terms of compressor life. For example, tests vary depending upon the viscosity grades of polyalkylene glycol (PAG). When you think of oil consider the miscibility. When you have 100% miscibility the refrigerant and oil mix well over a given temperature range. When you have partial miscibility the mix is limited at the given temperature range. "Immiscible" is when the oil and refrigerant do not mix. Remember it is the refrigerant that carries the oil to and through the compressor to lubricate it. Poor lubrication and you have compressor wear and failure. Though we do not claim to be "experts" in field we can tell you that we have assisted in converting over 1000 P cars in the past ten years to R134a; wobble plate and swash plate designs, in 911's, 928's, 944's.
99% of the time we use synthetic polyol ester (POE), such as Castrol, BVA and any other reputable brand, rather than PAG's. Ester's do mix well with residual R12 mineral oil.

It is well know today that many of the early failures with R134a related to either: failure to clean out the system after compressor trashed, failure to properly evacuate or charge the system (typically happens when a retail customer purchases a few cans of xxxx refrigerant at the local discount autoparts store and attempts to charge the system himself without knowledge or correct equipment).
With regard to R134a in P cars the bad hype is found more in the 911 or 930 which does not have condenser layout that a front engine 928 or 944 has.

As far as leakage with any refrigerant, it is all related to
time, pressure and the parts per million per linear foot of system tubing; or the size the "hole". A 911 or 930 has nearly 40 feet of rubber hose, a 928 or 944 less than 25% of that. Step into a 89+ 964, 993, 996 or later an much of the rubber tubing was replaced with aluminum tubing so the leakage tends to be less with the exception of failing compressors and evaporators.

With regard to the compressor, wear is all a matter of running hours and under what maintenance condition (if the system ever had a leak did they simply top it off or did they add lost oil).

<i> "If you evacuate a system designed for R-134a and use R-12 instead, what would happen?" The answer has UNIVERSALLY been this: "It would cool better and last longer." </i>
Not necessarily true. If you are taking a short cut, assuming the system used traditional PAG rather than Ester you are in for trouble as you won't have a good refrigerant/oil mix. In simple terms the difference between the two systems is that the R134a system most likely has
HNBR type o-rings (elastomers), whereas the R12 system had an older style Neoprene (there are modern or Super Neoprenes that perform better than old traditional), the R134a system has either a "XH7" or "XH9" desiccant whereas the R12 probably had XH5 which is not compatible with R134a. The R134a system, depending upon the year of design and state codes most likely has either a pressure relief valve or cut-off switch for system pressures. The key feature which may help with R12 is that "maybe" the condenser is more modern. However
if the thermostat or pressure controls turn on and off the system "normally" to prevent freezing of the evaporator core, your vent temps could most likely be the same with both refrigerants. What may seem like an improvement will more likely be an improvement in the ventilation channels (vents and ducts) in terms of quantity and location. Bottom line, if the car came with R134a (as most OEM's do since the R12 phase out) and it blew reasonably cold air within the normal range, leave it be.

However, if you want to try something other than common R134a as an alternative to R12, try something that is approved on the EPA snap list and something that your service shop (if you use one) is willing to service.

Well after converting from R12 to 134a my AC stopped working. I can hear the 134a leaking from the front of the compressor. The AC worked fine before but I thought it could use a boost of freon. Some ******* sold me the 134a and said it was R12 so I just converted it after draining the old stuff out first of course. Now since all the 134a leaked out would it be possible to go back to the old R12 stuff.

I haven't read most of the second page here so forgive me if i say something that's repeated or common knowledge to you.. but freon doesn't just "disappear"... if your system is empty (or doesn't have enough to cool you down) then there is a leak in your system somewhere... fix that first... then i'd reccomend a can of DuraCool - it's cheapish and the easiest solution (by a long shot).

I guess we can assume you had converted to another refrigerant because your system had a leak but the leak was not found or fixed?

And there is no mention of evacuation, the amount of refrigerant used or pressures, etc.

Going back to R12 or trying an alternative refrigerant would not be logical yet.

A suggestion. A have an ac tech find out what is the problem and quote you the cost to repair and pay him for his services. From there you can decide what to do next.

If you were to buy all the equipment (good ac vacuum pump and service gauges, refrigerant scale, tracer dye and light, electronic sniffer, recovering station and tech manuals) to do the job correctly one-time, it would not be cost effective (you can figure on doing at least 35 procedures before you would break even on the equipment).

And, be cautious of any "kits or packages" from retail stores or mail order ads which offer little cans of refrigerant with a single gauge attached to a hose. You still need all the right equipment and know how to make the system work correctly and reliably. (regardless of what you read about "yeah, well I did it to my car and it works great").
;)

griffithstech

No actually before the conversion everything was working fine. I just though I needed a boost of freon. There were no leaks before the conversion only AFTER. I learned the hard way if aint broke dont fix it which is basically what I did. I may take your advice and have it diagnosed before I buy anything else for it.

griffithstech,

Those "kits" we are suppose to be cautious of....do those include the ones from griffiths? Does your boss know you are telling us not to buy kits from there? You sound to me like someone that has attended a lot of classes but as far as really applying it in real world, I'm questioning that. If you tell me that R134 cools as well as R12 (that's when I questioned your credibility) tells me either you are either echoing what some instructor has told you (we do that in the computer business as well...buy blades servers, they are better..yeah right) or you haven't lived in the Texas heat. I will probably still buy a kit somewhere and I'll do it like I did when I rebuilt the a/c system in my Grand Prix. I don't have all the tools you mentioned but i usually have enough at my disposal to get the job done. As far as the leak detectors, they help some but aren't that accurate. I broke the compressor lines loose by accident on my Grand Prix when I was doing some work on the engine and so I took it to a repair facility to have them reattach the lines and charge the system...basically fix what I broke. They called me back and said that they reattached the lines and their leak detector was telling them that the compressor was leaking around the front shaft seal and I needed to replace my compressor. I brought it home and resealed the lines, changed the dryer, vacuumed it and recharged it with one of those hoses and gauges you said not to use and it's been fine every since. Still not as cold as an R12 system but it never has been even when I bought the car new. So much for the leak detection systems. In some instances, those inexpensive gauges aren't going to work. They can't tell you the high side pressures and therefore can't tell you the expansion valve is plugged or anything like that, but if you are not in the situation where your a/c is giving you problems, then that's probably not something you need to check for. Thanks for sharing your education with us though, that could come in handy. I have to wonder why you are here on a do-it-yourself forum telling us to take our cars to garages which probably won't buy your parts. I would think you would be encouraging us and helping us to find ways to do it ourselves and promote your own products.

Good information here - thanks for that.

My concern (after blowing out a high pressure hose on regular old r-12) is that the additional stresses associated with running r-134 on an older system may not be worth the risks unless EVERYTHING (all the hoses, etc.) have been recently replaced. Remember, these things could be as much as 23 years old on some of our cars and now you're going to put MORE pressure in them?

Just my $0.02, but I'd say r134 would be great if you've replaced all the hoses (and probably the condenser, since it's a bit undersized for r134 use), otherwise go down to Tijuana, load up on r12 or get one of the substitute refrigerants mentioned.

BTW the Griffith's stuff ROCKS! I'll shortly be ordering a flush kit and vacc. pump from them in order to service my 951's a/c system, which has experienced the dreaded "black death". I'll probably run freeze-12 or duracool in it when complete, FWIW.

From what you have now pieced together (you thought "needed a boost"), I would speculate that you had a leak before hand and the system high side pressures were lower than normal, and most likely it was the nose seal to begin with or excessive high side pressure blew it out. You'll never know as there were not high side pressures noted on a gauge to refer to.

Nose seal leaks on an on nippon are common.

And, yes, pay the fee and get a confirmed "cost to repair" next time around.

I don't see how your sarcasm is helping anyone in this post. The forum is open to helping individuals rather than
hindering them. However we'll try to respond so others can read both sides of the coin.

<b>Originally posted by Razorback1980
<i>Those "kits" we are suppose to be cautious of....do those include the ones from griffiths? </i> </b>
You are confused. "little cans of refrigerant with a single gauge attached to a hose". Sorry we don't sell them nor promote them obviously. We provide more thorough "kits" that typically include a complete new compressor in terms product of interest in this forum (the 924s,944,951 and 968).


<b><i> Does your boss know you are telling us not to buy kits from there? </b> </i> Yes and no. I'm telling readers to be aware of the limitation of the certain products offered to the retail market that so suggest that the user has knowledge or equipment to do the job correctly.
We are not referring to "compressor kits", however if you are interested we expressly state that the retail customer should " leave the evacuation, charging and testing to someone who has the right equipment and experience".

<b> <i> You sound to me like someone that has attended a lot of classes but as far as really applying it in real world, I'm questioning that. </b><i/> I think if you were to query the list of customers we have satisfied since 1984 they would not agree with you in total. And, I won't say that we are "the experts" but I'm confident to say we have seen and helped resolve many P car customer problems

<b><i>
If you tell me that R134 cools as well as R12 (that's when I questioned your credibility) tells me either you are either echoing what some instructor has told you (we do that in the computer business as well...buy blades servers, they are better..yeah right) or you haven't lived in the Texas heat. </b><i/> You know that R134a has a lower high side pressure than R12 below 60F and converesly has a greater high side pressure above 85F or so. It has been our experience, and our customers, that R134a when properly serviced (having and excellent vacuum and fine tuned qty.) performs very well in a 944 up through 95F. I will agree above 95F you may notice warmer (but not severe) vent temps in a 944 with a stock condenser. However our comments are not directed specifically to the TX community (this is a worldwide forum). Southern Cal, AZ, TX, AL, FL are extreme areas as compared to the quorum.


<b><i>As far as the leak detectors, they help some but aren't that accurate. </b></i>
Any tool is as good as the person using it and their awareness of its limitations. I myself have had an electronic sniffer register a leak at one moment on one component, however after "double checking" the suspect leak a second later it disappeared. This is usually caused by a stray gas in the air or contamination on the sniffer tip.
It is not the a sign of a truly failing component.

<b><i> In some instances, those inexpensive gauges aren't going to work. They can't tell you the high side pressures and therefore can't tell you the expansion valve is plugged or anything like that.....</b></i>
I disagree. The gauges do tell you where to start looking.
One scenario with regard to the exp. valve would be a low high side and low low side reading which would suggest a valve that is stuck closed. However unless you were aware of your total refrigerant charge (ie. by weight scale or charge cylinder) it could also mean simply a low charge.
FYI an expansion valve failure is not common a 944 and if so tend to happen when the compressor breaks down
(seizure) and contamination gets past the drier.


<b><i>
Still not as cold as an R12 system but it never has been even when I bought the car new. </b></i> A few friends once told me that they thought the 85/1's blew colder.
Without knowing the ambient of a given day, system pressures, degree of vacuum in microns and refrigerant charge I can't comment as to how well you think the system should be cooling.

<b><i>
Thanks for sharing your education with us though, that could come in handy. </b></i> Tom, maybe it will someday.

<b><i>
I have to wonder why you are here on a do-it-yourself forum telling us to take our cars to garages which probably won't buy your parts. </b></i> "us" hmmmm.
Well I read the forums, like you do because they are interesting. I don't recall nor can I read a post that say's "don't bother fixing everything yourself". If you don't have the tools (ac wise in terms of this thread) to do the job and you can't borrow them then obviously you have to take your car to a shop. However not everyone here fixes all their own problems and you will probably find other forum members that happen to be producers or shop owners or techs posting.

<b><i>
I would think you would be encouraging us and helping us to find ways to do it ourselves and promote your own products. </b></i> Well you are right. I am encouraging you to think twice about buying a product you may not need or be able to service yourself, whether it be "ours" or someone body else.

A good point.... if it's old what else will break? Well, the first high side hose (compressor to condenser) does fail due to its location and environment (pressure and heat).
For some reason the second two high side hoses (on the liquid side), condenser to drier and drier to exp. valve do not fail as often, but they do fail. I would suggest the more common failure of the compressor to condenser is the relative gas temperature it sees prior to cooling of the gas at the condenser.

Actually, I didn't see how yours was helping anyone. I started this thread to find out who offered the best replacement parts to replace an entire system for one that was probably past it's normal life. Just to find out if anyone had any experience replacing their whole system. What it feels like to me is that a lot of people posted what they did and you continuously interjected your opinions and told us all we were wrong and how we shouldn't use duracool and other such products when many people have posted success stories about the product. Although that isn't my intentions for the long term, it may very well be a good short term solution. The forum members also said that Griffiths had a decent kit to replace the a/c products on the 944 which is what the post was really after if you care enough to read it all, but you seem very opinionated on how you believe it should be done and your method is the only acceptable one. I don't agree. I think there are many ways to accomplish our goals of how to make our a/c systems work and yours isn't the only one.
Read the "In some instances" paragraph again. In that paragraph, I said the small gauges are not going to diagnose problems within an a/c system and then you said you disagree? Perhaps it is you that is confused or ....I don't understand your comments on that...if you have problems with an a/c system and you don't know exactly what the problems are, a small pressure gauge attached to a can isn't going to help with that, you have to be able to look at the whole system not just a small part of it which is what you were trying to say earlier so one of your statements is contradicting the other. But I think that if you know you have a small leak and you don't need to put your system through a fifty point inspection every six months just to fill it again, then perhaps the small gauges will work just fine and you don't need all that equipment you were stating was necessary and you can't cost justify taking it to a shop for one can of freon every six months. When it comes back from the shop, it's probably going to do that anyway. I also don't think that telling people to take their car to a certified a/c person is helping anyone here either, if we don't know how to fix our cars and the good folks here can't help us, we can figure out that we need to take the car to the shop without any help.