| Author |
Message |
Torai Madjid (Countach83)
| | Posted on Thursday, August 09, 2001 - 5:42 pm: | |
Topping off with another compound over R-12 is partially a matter of legality, avoiding contaminationof reclaiming equipment, and control over what is in the system.
Cross contamination when reclaiming refigerant is a big problem. That is why the EPA wants unique connectors used which each different refigerent type.
The other problem is the interaction between the gasses. Example: Tin/Lead alloys melt at much lower tempratures then either pure metal.
Having non-condensibles and moisture is bad, so it is better to reclaim the R-12, replace (or bake out the receiver/dryer if unavailable) and pump down the system for 4-12 hr.
I think it should be easy enough to get somebody to take the R-12.
Don't forget to check compressor oil level if the system is opened. Systems which are constantly topped off also leak the oil which travels with the refigerant.
There is also getting more R-12. R-12 is 1/3 the price of 2 years ago, because it is now mostly reclaimed, and supply is plentiful. High enough to crimp the 134a market. Of course shops make more money on 134a conversions, and even more when compressors fail several months after a shoddy conversion.
I imagine there is a lot of interest in DIY A/C because of the Ferris Bueler factor. |
Greg Rodgers (Joechristmas)
| | Posted on Thursday, August 09, 2001 - 12:08 pm: | |
With Autofrost and other r-12 substitutes most compressor companies won't offer warranties if these blends are used. Now, I have heard that Autofrost can be used to top off an R-12 system. As Autofrost was originally formed as an R-12 booster. So, why do the instructions say to not top off? Is it because of cross-contamination? |
Warren E. Smith (Magoo)
| | Posted on Thursday, August 09, 2001 - 11:18 am: | |
Greg, I can't add anything to what Toria just commented. He covered it all. |
Torai Madjid (Countach83)
| | Posted on Thursday, August 09, 2001 - 10:57 am: | |
Autofrost is R-406a which is one of the new blend refrigerants, which is compatible with mineral based oil. Mineral based oil is completly soluble in R-406a. Solubility is essential, otherwise oil collects in the evaporator and lines, not in the compressor where it belongs. When the compressor is located at a high point, and has long lines (like the Countach) this problem is magnified.
Freeze-12 mentioned in this thread exhibits poor mineral oil solubility. Mineral oil is completely insoluble in R-134a which drives the need for other types of oil like PAG and POE. Those oils are poorer lubricants, and like brake fluid, absorb water which leads to corrosion.
R-406a does contain 4% butane, but this is not enough to make it flamable. The butane is there to improve oil solubility. It is compatible with desicants used with R-12, and does not rely on hygroscopic lubicants like PAG and ester oil.
It can be incompatible with some York, Tecumseh, and Chrysler RV-2 compressors, because the R-22 in it is not compatible with Buna-N seals. It has smaller molecules, so it will leak faster.
As with all blend refrigerents, charge and top-off procedures are different.
Cooling performance of R-406a and many of the other R-4xx blends is better than R-12, not worse like R-134a. Head pressures are usually lower, which does not push the need for installation of high side cut-off switches.
In an ideal case, R134a can work well, but the bases need to be covered to prevent latent failures: new receiver drier for 134a, thorough pumpdown of system, flush and removal of mineral oil, presence of high side cutoff switch. R-134 has the advantage of being single component, so normal top-off procedures apply. Lower efficency, and higher risk with systems with high mounted compressors and long lines are cons.
The R-4XX blends provide better performance with less changes, and less risk of internal corrosion and compressor mechanical failure. R-406 cons include incompatibilies with some seals, higher leak rates, and more complicated top-off procedures. I consider compressor seal failure as lower impact, since they are easy to change (avoid new-old stock Buna-N seals; get neoprene), and don't throw burnt oil and shavings into the system. |
kelly vince (Tofosi1)
| | Posted on Thursday, August 09, 2001 - 9:51 am: | |
Here's what I did to my 308 and it works.I posted this on Ferrari list about a month ago. The system seems to be working about the same. If I get in the car hot, 93 degrees or better outside, it takes a while to get down to 50, but mostly now in Tarffic it runs at 50 highway 40. I'm now changing the coolant hoses, so I have not run it in three weeks. I take my time and have fun working on it.
One thing I am proud about is this car had not AC run in the last 8 years.
> The drier I used is a
> SCS/Frigette
> Part #
> 207 805
> XH9 DESICCANT
> WWW.scsfrigette.com
> Purchased at a local ACdelco AC shop for $49.00
>
> Expansion valve
> Murray Climate Control
> PART#
> MRY 38683
> THP AC3801C
> UPC 9636138683
> NO WEB SITE THAT I CAN FIND
> Purchased at O'Riely Auto Parts for $26.00
>
> High and Low side 134A connectors,
> high side $6.99,
> Low Side $15.00.
> Purchased at NAPA
> DON'T buy the Aluminum cheap ones.
>
> 3 cans of 134A Wal-Mart $4.88 each I only used 2
>
> 134A O rings Assorted $5.99 Autozone
>
> 2 8oz cans of ester oil
>
> I changed all O rings. took out the 2 Schratter valves and replaced them
> with the 134A connectors.
>
> I used an Aquarium air hose to drain the oil from the compressor. I
> siphoned it out, got about 8 OZ. added the ester until it would not take
> any more about 11OZ. Manual call for 330CC or 11OZ. I used a turkey baster
> to add the oil to the compressor.
>
> Drier remember not to open or connect it to the system until you are ready
> to Evacuate.
>
> Make sure the oil drier did not dump any Desiccant in to the hose going to
> the expansion valve. this is what killed me.
>
> Yesterday to was 93degrees here in traffic I got 60 degrees high way 50
> degrees. all reading from the lower vent.
>
> This evening 83 degrees, 86 heat index 40 Degrees at the lower vent.
>
> I have noticed one thing. Before my car ran at right below 195 on the
> highway, traffic right over 195, no more than the width of the needle. Now
> highway the needle is mid way between the 195 and the next hash mark. In
> traffic it stays on the hash mark. This mark is between 195 and 250.
>
> I will double check the car tomorrow to see if I have developed an over
> heating problem that may be unrelated to the AC. I did get a little air
out
> of the front radiator when I got home tonight. I'm going to drive it
> without the AC on.
>
> Per Neville in England I'm going to over fill my expansion tank. It's been
> about 2,000 miles since I have done this. When I had this over heating
> problem before, over filling fixed it. It cooked off what it didn't need
> and has been find ever since until now.
>
> OF course I am not responsible for anything that might go wrong with your
> car in this process. This is only what I did to make it happen. And to all
> your Ferrari Techs out there, please excuse my ignorance if I have said
> anything that sounds stupid.. Thank God I got some common sense from my
> father. I wish he were still here with me to take a drive.
>
> Kelly Vince
> Do you have the Passion?
> Tofosi
>
>
> Sincerely,
> The Vince Family
> [email protected]
> 39599 Cedar Lane
> Pearl River, LA 70452
> Home 504-863-7717
> 1980 308 GTSi SN#33701
> |
Greg Rodgers (Joechristmas)
| | Posted on Thursday, August 09, 2001 - 8:11 am: | |
Magoo, do you know about Autofrost? I haven't heard much about it but I think it contains Butane if I am correct. I wouldn't think that this would be the safest freon to use. |
Greg Rodgers (Joechristmas)
| | Posted on Thursday, August 09, 2001 - 6:20 am: | |
Magoo, I am not mixing. "Freeze 12" is different than 134a. With Freeze 12 the previous oil can still be used provided it is still all present. In many places you have to be licensed to purchase Freeze 12 and Autofrost as well as the original CFC-12 (R-12). Freeze 12 actually contains part R-22. |
'75 308 GT4 (Peter)
| | Posted on Wednesday, August 08, 2001 - 10:21 pm: | |
Damn, they don't sell any R-12 up in Canada (illegal).
Are these cans of refill R-12 avaliable in WA? (I'll gladly smuggle it across the border, just like the rest of my parts for my rebuild J. You should've seen the expression on my face when I called Canada Customs to ask how much it would cost to import a clutch.... $110 alone in duty and taxes - GST & PST!!!). F--- you, sent it to my US P.O. Box and then in the trunk of my car!). |
Warren E. Smith (Magoo)
| | Posted on Wednesday, August 08, 2001 - 4:23 pm: | |
Greg, Donot try to mix R134 with R12 it won't work and is not compatible with the R12 REF. oil. R12 can still be bought by a licensed refrigeration tech.only. Very expensive though. Unless you convert over to the R134A, R12 is what you have to use. |
Greg Rodgers (Joechristmas)
| | Posted on Wednesday, August 08, 2001 - 3:57 pm: | |
I just called my local Pep Boys and they said they will no longer sell "Freeze 12" without a license. I was surprised because it was $8 a can and could be purchased over the counter. My system has no freon. The system was drained by the PO when the belts were done. |
Gene B. Radcliffe - 308 GTS (Brcbank)
| | Posted on Wednesday, August 08, 2001 - 3:43 pm: | |
To quote a seeminigly knowlegable site:
http://www.griffiths.com/achelp/achelp3.htm
"R134a is the most widely accepted alternative automotive refrigerant used to replace R12. There are other refrigerants: some of which may work, some of which don't work, some of which will destroy your a/c system and some of which are dangerous."
Go there to read the whole FAQ. |
Octavio Mestre (Alfab4308)
| | Posted on Wednesday, August 08, 2001 - 3:40 pm: | |
Gregg, no freon or low freon? |
Greg Rodgers (Joechristmas)
| | Posted on Wednesday, August 08, 2001 - 1:14 pm: | |
My 308's A/c is not working due to no freon in the system. I am quite sure it doesn't have any leaks. Do I need to add oil to it or can I just recharge the system? Thanks. |
Octavio Mestre (Alfab4308)
| | Posted on Wednesday, August 08, 2001 - 10:39 am: | |
I have recharged my a/c a couple of times with "replacement" R-12. I can't remeber the brands but I know the cans had different names. I am not sure, but I think they change some minor chemical component and sell the stuff as being different from R 12 until the EPA gets on them. The cans I used specifically said that the chemical harmed the ozone layer.
As far as the oil, I never changed it and my a/c worked fine for over a year before I needed to add another can. Again, I think this stuff is really R-12 under another name. For what it is worth, I have also seen some a/c shops using this stuff. Good luck |
Scott Gold (Scotttgold)
| | Posted on Tuesday, August 07, 2001 - 11:52 am: | |
Does anyone have any ideas on how to charge the AC unit with R-12? I have a friend that says he can charge it with some new stuff that is supposed to be a R-12 replacment. I believe it's called ASPEN R-416A. Is this stuff safe?
Do I have to change the compressor oil?
Thanks,
Scott |
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