dprantl

An R134A system is also very easy to service yourself. You need to do some more work up front, but really, replacing o-rings is not that hard.

Dan
'91 928GT S/C 475hp/460lb.ft

David L. Lutz

For what my 2 cents is worth; The system was designed for R12and I would stay with R12. It only takes 3 14oz cans to fill the system if I remember correctly. You can easily buy a few cans on ebay. (Check WSM for the correct amount by weight w/rear air)

I just completely removed my system, replaced all "O" rings, drier, expansion valve. (added the correct amount of oil after the flush) Pulled the vacumm overnight and filled the system and it is ice cold and been that way now for 3 months. NO Problems. I couldn't ask for a colder system!

dr bob

Hmmmm.

Citing a website that mentions the contents as HCFC... It's a blend of isobutane and butane/propane, mixed with R-134a. It is most certainly flammable. I guess one person's description of 'flammable' may differ from another person's description. Maybe someone doesn't appreciate the flammability of the mixture, especially if they test by poking a hole in the top of the can and holding a match to it. I have fairly extensive experience with isobutane and butane plends in industrial environments, and would not want to risk the fire. Think along the lines of a BIC lighter with a pound or more of fuel available.

I'm also a big fan of avoiding 'make-do' solutions when a real, legal option exists. To make any option real, you need to fix all the leaks before you charge with anything. If you didn't have leaks you wouldn't be considering any of these solutions, right? So replace the o-rings, maybe the hoses, replace the drier (need to do that no matter what refrigerant you choose), drain and replace the oil in the compressor while it's out on the bench for the o-rings in the manifold plates. Now evacuate. Only at this point you need to decide what refrigerant to put in. Tough choice? Hardly.

If you choose not to reseal all the leaks, and just "top off" the R-12 remaining in there now, the blended stuff will fractionate out, leaving the heavier HC molecules. Yeah, it's a DIY, has to be, because no regular service shop will touch that stuff or your car once you contaminate it. Plus.... Damn, the thing still leaks, so I'll add some more. Higher HC concentration, more flammable, and the darn thing still leaks. Getting the picture?


Fix your post.

dprantl

While this would be the correct approach for most vehicles originally equipped with R12 (unless there is a parallel-flow condenser available for it), this is just not true for the 928. The 928 has such a huge condenser in relation to the cabin size that it can easily cool down the cabin with R134A. Many people have done the conversion to R134A the right way and have 32 deg F evaporator temps in 100 deg F humid weather (including me, with a black/black car even). It doesn't matter if you have liquid nitrogen in the system, it can't get colder than that. If you're going to go through all the trouble you did above, I can't fathom why you wouldn't use R134A; just MO.

Dan
'91 928GT S/C 475hp/460lb.ft

BrettStrikes

Fix the leaks and add a few cans of Freeze12...its a cheap and viable option for the lay person...no worries about licenses or certifications...NONFLAMMABLE mixture to everyone except for Dr.Bob...*shrugging*...guess he is a doctor of refrigeration...You are probably someone who is also concerned about the gas tank being full of fuel near the rear positioned battery in our 928's....or maybe even being struck by lightening...everyone knows...anything can happen...but...NONFLAMMABLE Freeze12 exploding is not something that should concern most people....again...unless your name is Dr. Bob....

Fix your A/C *L*

dprantl

Freeze-12 HMIS & NFPA Flammability Rating: 2
http://www.technicalchemical.com/msds/6030.pdf

R134A HMIS & NFPA Flammability Rating: 1
http://ww2.ramapo.edu/libfiles/HR/En.../HVAC/134a.pdf

Freeze-12 also has a flash point lower than 300 deg F. And as Dr. Bob has said, topping up with Freeze-12 will create a mixture of less R134A and more of the flammable stuff. I don't understand why people keep saying Freeze-12 is "non-flammable", this is simply not true. I guess you can say that Freeze-12 is much more flammable than R134A or R12. Is that better for you?

Dan
'91 928GT S/C 475hp/460lb.ft

BrettStrikes

This link states that Freeze12 is nonflammable
http://autorefrigerants.com/co00030.htm
....and based on the Chemical pdf's...134A is almost as volatile...you guys are missing the point of my original post....just giving advice on replacements....and Freeze12 is a viable one....

dprantl

Ok, so your source is some internet seller of Freeze-12, while my source is the NFPA... you know, the one whose label is required on any commercial shipment. Who are you going to believe? Saying Freeze-12 is non-flammable is a blatant lie, seriously. And what do you mean R134A is "almost" as volatile? Where is your source for this? Did I not list its properties in one of my links? Did you see for DOT standards it doesn't even have a flash point? Do you know what a flash point is?

Here, I know how this can be solved once and for all. Anyone who is 100% convinced that Freeze-12 is "non-flammable" like that internet seller suggests should go buy a can, then set up a camera of themselves holding an iron rod heated to 1000 deg F in one hand and discharging the can in the direction of the iron rod with the other hand in a close proximity. Please, I want to see this video!

Dan
'91 928GT S/C 475hp/460lb.ft

BrettStrikes

The front of the Freeze12 can states it is nonflammable and contains no CFC's...thats from the manufacturer..if you know more than the company that makes the stuff shouldn't you be sending them posts for a CEO job or something instead of wasting your expert time here?

JHowell37

They may say it's not flammable but the MSDS on their site states that the flash point is below 300 degrees.

But that aside, the fact of the matter is that if you've got a 20+ year old A/C with all components and seals the same age, when the r-12 leaks out, it would be a wise choice to examine everything, change the expansion valve, drier, o-rings, and possibly the rubber hoses. Since it is not uncommon to lose oil when you lose refrigerant, it would also be wise to drain out as much oil as possible so you can measure what you have and replace it accordingly. At that point, what advantage is there in using products that aren't widely available and cost more money?

Their ads ignore the fact that the newest vehicles with R-12 have been in service for 14 years. 14 years is a long time. It ignores the fact that driers and expansion valves/orifice tubes should be replaced after 14 years. It ignores the fact that most o-rings will show significant deterioration after 14 years. The stuff essentially endorses band-aid fixes for problems. I can understand why. It's better to have people buying $30-$50 worth of their products each year then have them buy a few cans of R-134a once.

As for whether it works better is anyone's guess. What I know is that my A/C can blow 28 degree air when the ambient temp is about 84. And that's using R-134a in a 23 year old compressor that can be easily turned by hand. Dr bob's car has shown 20 degrees on a warm day. I find it hard to believe that this magic potion can improve on those numbers.

SharkSkin

Louie's refrigerant fire

Not posting this with the intent to be alarmist -- the product involved was not Freeze-12, BTW. I don't know how similar or dissimilar Freeze-12 & Enviro-Safe are, but I would hazard a guess that memories of this story may be influencing some people's reactions to the idea of flammable refrigerant.

It's not clear to me what difference it makes, if a line is compromised and you end up spraying finely atomized(flammable) oil onto an exhaust manifold vs doing so with the addition of some percentage of isobutane. I think you run the risk of fire either way.

Having said that, I'm sticking with R-12 just the same.

BrettStrikes

Based on Howells post...........
He even solidifies my point even further....why change everything over when you can fix whatever leaks you have and utilize an R12 compatible replacement for a fraction of the cost....Freeze12 is readily available and not a difficult to find "magic potion" as one may think...and costs less than anything you can put in your system to create cold, safe, NONFLAMMABLE air....period.....

stolarzj

I'm trying out ES12A Industrial in mine, I just replaced all the o-rings, hoses, drier, expansion valves and compressor. The ignition point of this refrigerant is 1246 degrees. If I don't like it then I will just switch to R134A. The ES12A is at least better for the environment it's all natural stuff, nothing man made and it's even endorsed by Green Peace.

JHowell37

I don't solidify your point.

Post a picture of your center vent temps, and we can end this debate.

dr bob

... With R-134a you can buy cheap at Wal-Mart. Why would you make a bastard system using non-standard refrigerants when you can use R-134a? And freeze your fingers to the wheel...