r12 to r134a retrofit...

[safariobsession]

I might tackle converting the AC on my 91 from r12 to r134a this weekend. I've done a lot of reading in the past year about retrofits...(horror stories, success stories, parts needed/suggested, etc.) Searching the forum I didn't see anything posted about this yet and was wondering what you guys have done or heard about the conversion.

I hate to have to change all the AC lines and everything as what is suggested by some. I have all the essentials now (adapters, r134a, vacuum pump) except for the compatable oil. Any thoughts?

[LaGrasta]

All o-rings and dryer to.

[LaGrasta]

nostalgicairparts.com/

Jon was a great help to me and his prices couldn't be beat.

[Smiliesafari]

While you are changing the 'O' rings and have the lines disconnected, flush the evaporator and condensor with acetone.

[safariobsession]

Thanks guys. It's looking to be more of a "job" than what most retrofit kits explain. Flushing with acetone....is this an easy task? What is involved? Is there a drain on the compressor to drain the mineral oil out? Should I or do i need to drain the old mineral oil out? Thanks again.

[peter]

WAIT!!!!!!!!!!!!


Newsflash, boyz'n gurlz. R-134A is slated for a phase-out within 10 yrs. Yeah, you read it right. Greenhouse-gas effect is unacceptable.
We (HVAC & refrigeration contractors) have been bouncing around from one replacement gas to another. We are now using R-414A as a drop-in replacement for R-12, MP-39, R-409A & R-134A. According to what my supplier has told me, this refrigerant works with any oil, from mineral (used in R-12 systems), to alkybenzene & polyoester (semi-synthetic & synthetic).
However, do NOT take my word for it. My info is based on my suppliers info, which has been woefully wrong in the past. Research it on the 'net yourself

[Smiliesafari]

Good info, Peter. But 10 years? I'm so old I won't be here in 10 years. For right now we have to work with what we can get. And for a lot of us "cheap" is necessary. Flushing the AC components is no more difficult than just pouring it in one end and letting it pour out the other. Use compressed air to blow out the condensor and evaporator. I'd use at least a quart. Don't worry about what's left in the compressor. That amount will be very small.

[CaptSquid]

I wonder if it's possible that the Greenies would MAKE UP THEIR FLIPPIN' MINDS!

[peter]

Ditto, squidster. As far as using compressed air to blow out the lines, that's generally a big no-no. Compressed air usually has alot of moisture in it, which is THE worst killer of an HVAC & refrig. system. If you're hell-bent on using air (or don't have nitrgen which is the only accpetable means of pressurizing a system), at least make sure you've run the air thru a water separator. Still not a good solution, but better than nothing at all.

[Rileysowner]

Just the enviros making another crisis. I read this a while back on another group I subscribe to while we were discussing Global Warming oops, Climate change. Enjoy.

Back in 1974-75, I was a graduate assistant in the
> Automotive Technology Dept. at Western Michigan
> University, Kalamazoo, MI. While there, one of our
> faculty attended a national conference studying the
> effects of various factors on our atmosphere, one of
> them being the automotive refrigerant, R-12. At the
> conference, carbon based R-12
> (Dichlorodifluoromethane) was declared to be an ozone
> depleting gas. Well, R-12 is a heavier than air gas,
> and is extremely stable (i.e. does not combine with
> other substances or decompose except very, very
> slowly). The only way it changes rapidly is to burn
> it, in which case its major by product is phosgene gas
> (a nerve toxin used in WW-1 which decomposes very
> quickly).
>
> The only problem with the above declaration is that
> any rockets used by NASA, etc. for scientific purposes
> had not become common by 1975, meaning that none of
> them had ever been used to study the effects of R-12
> on the atmosphere by then. Do you understand the
> implications of what I just said? What I have said is
> the whole subject of R-12 and ozone depletion was
> based on a total fabrication by the environmentalists
> who wanted to create a crisis. To my knowledge, there
> still has never been a scientific study of the upper
> atmosphere with the intent to measure the levels of
> R-12 (remember, it is heavier than air) that might be
> found there.

[SoCalli V8]

I would recommend fitting an electric condensor fan also (any engine cooling fan will do) blowing through the "a/c radiator" it will help provide lower temps inside the cabin area.

Power it using a relay which is triggered from the a/c switch positive, so that it runs all the time while the a/c is switched on.

[safariobsession]

Thank you guys. Peter, I took a look into the R-414a "Autofrost" which seems to come up as R-406a in many places. No question on the compatability with the original oil but on availability (also requiring the certification). In the past i've looked into Freeze-12 which claims to be compatable with both mineral oil and existing R12 Freon in there. (Still clicks the compressor on for a second and off for 4 or 5) It seems there is more of an abundance of freeze-12 on ebay now too. Just have to check into it more.

Haha, yea i agree there's something fishy with the government saying the refridgerants are "bad" for the environment.

[sfeaver]

Does the system still work? Why not just fill it back up with R12? R12 isnt cheap, but retrofitting isnt cheap either. And R134 will not work as good in your R12 system as R12 will.

[safariobsession]

Does the system still work? Why not just fill it back up with R12? R12 isnt cheap, but retrofitting isnt cheap either. And R134 will not work as good in your R12 system as R12 will.

System still works. It has never been "empty" in its lifetime. We charged it with our last can of R12 back in summer 2003 and that charge lasted about 3 years before it started cycling on and off and blowing warm air. Right now it blows warm but clicks on for about a second and off for about 4 or 5, so there's still a good amount of R12 left in there.

I might be able to get a hold of a can of R12 from a friend's dad but I just bought a couple cans of Freeze-12 on ebay.

From what I was able to find out...

From one thread at http://www.thirdgen.org/techboard/cooling/ Much more info there too.

Freeze 12 is not propane based, and is not explosive. Freeze 12 is 80% R134a, and 20% R142b. No flammable components. The R142b in Freeze12 produces a blend with lower head pressures than R134a alone. Freeze 12's pressure curve is remarkable similar to R12. A lot say it's OK to top off the r12 with Freeze-12. Others say the system should be evacuated first....mainly for legality issues. It's said to be 100% compatable with the original mineral oil but recomended that 2 oz. of Ester oil be added if the system is evacuated.

Other refridgerants...
Hotshot/R-414b/KarKool is 50% R22
R-406A/GHG/McCool is 55% R22
GHG-X4, Autofrost/Chill-It is 51% R22
GHG-HP is 65% R22
GHG-X5 is 41% R22

You do not want to use any blend with any R22 in it. The R22 component of the blend will cause the compressor shaft seal to burn out, and will saturate the desiccant in the accumulator, displacing any moisture contained in the dessicant into the refrigerant stream (can we say "corrosion")

[sfeaver]

For the cost of the R12 that is the way to go, they still sell it in the USA. I already went through retrofitting my 89 Lesabre, replacing the fauity parts, flushing completely etc. R134 just isnt cold enough, so I got my hands on some R12 and thats how it is now. And it blows real cold.

To get an alternative refrigerant to work even half-assed you would need to replace the condensor and add a fan. Flush the old oil, vacuum it out and refil. If it still has some R12 in it and it lasted for three years then that isnt a major leak. But really still should be fixed. But if it still has some charge then should be able to top it up.
Cycling on for a second and off for five means that there isnt much charge left, I'd say less than a pound.

Scott