AC R134 Retrofit

[Guest]

Hi guys,<P>I am planning on converting my '69 Skylark Convertible from R-12 to R134. The AC hoses were disconnected when I bought the car. Do I still need to have the system evacuated before changing the oil in the compressor?<P>I was planning on changing the compressor oil. flushing the system, changing o-rings and replacing the drier on my own and then taking the car in to have it charged. Does this sound like a good plan or am I missing something?<P>Can I evacuate and charge the system myself? I don't have a vacuum pump or AC guages. Can this equipment be rented and used by someone with no AC experience?<P>Thanks,<P>Ron*

[Guest 70 Electra]

WHY??<P>This is bound to raise some controversy, but WHY switch to R134a? Are you THAT worried about the environment??<P>Your system is designed to operate with R12 and will not function as well with R134a. Pressures will be higher, discharge air (dash vents) won't be as cold, and compressor life will be shortened (due to the oil used with R134a, not the refrigerant itself).<P>If you're looking to save $$, the conversion is false economy. Instead of $50-60 per pound for R12, you'll pay $10-15 per pound. BFD! (Big F***ing Deal). There's only about 4 pounds in the whole system anyway. <P>The few bucks you save initially will be forgotten as you struggle with a poor performing system and reduced component life.<P>I'm sure you'll get differing opinions, but I've been down this road.<P>Regarding evacuating the system yourself--don't try it unless you are experienced and have the equipment. Again, the few $$ you MIGHT save do not justify the risk of ruining something (at worst) or wasting the refrigerant charge (at best).<P>Don't forget--there's reasons why the industry resisted switching to the new refrigerant!

[YellowLark]

The argument about R-12 and the environment is long over. R-12 lost. Federal law mandates it's elimination. I don't think it's even being manufactured any more at this time.<P>You are right about R-12 being more efficient in R-12 designed systems, but the well is running dry, and R-12 will continue to jump in price as the remaining supplies dwindle.<P>Why discourage his making the conversion now? He will have no choice further down the road.

[The Old Guy]

If you are serious about changing to R-134A ,you should also change hoses. The new barrier hoses are lined with a material impervious to the gas. the new stuff will seep through the old hoses. This means you will be adding refrigerant every year

[Guest]

Gentlemen, I do have to say that there is another alternative. Find a good commercial refrigeration shop and ask if they can charge your car with refrigerant RB-276 which is about $19-20 per pound. RB-276 does not need an oil change because it IS compatible with the mineral oil that is already in your system.<P>I have used it on a few cars now and it does not cool as well as R-12, but it does cool as well as a retro R-134 job. I can find no downside in doing this.<P>Yellowlark is right, the price is never coming down on R-12, it has not been produced for years and it will literally go away.<P>Retrofitting is the only answer and I recommend RB-276 because of it's low cost and compatibility. I must caution on thing though, it does not seem to work real well on the newer GM orifice tube systems, I cannot figure out why yet. It does work well on the older expansion valve systems.

[Guest]

Well let me throw some more coal on the fire here.......<BR> Im not a big fan of R-134 myself and my bottle of R-12 is dwindling.......so I did some research. <BR> There are a lot of butane based refrigerents out there that will work and cool better then R-134......<BR> Now someone will say ...but they are flammable.Yup and so is the gas in the gas tank/fuel lines/ and carb. If you have a fire that bad I dont think your going to be around the car!<BR> Try these links if you want to see the alternate refrigerants. <A HREF="http://duracoolky.com/" TARGET=_blank>http://duracoolky.com/</A> <A HREF="http://www.es-refrigerants.com/" TARGET=_blank>http://www.es-refrigerants.com/</A> <BR> Or just do a internet search for alternate refrigerants.<BR> Good luck and hope this helps more then confuses!<BR>Tom H.

[Guest 70 Electra]

Just because R12 is not being made in THIS country, doesn't mean it will not be available in the future. Where do you think all the R12 from "old" systems is going? It's being reclaimed by the AC shops and sold back to us (at ridiculous prices!). There are NO laws to prevent anyone from using R12 in a car that was designed for it. The only problem is the old supply/demand situation on the refrigerant itself. <P>It's like anything else on your car restoration: How "right" do you want it to be? How well do you want it work? I don't dispute the R12 will cost more initially. My point is that the performance tradeoff is NOT the only drawback with R134a. I still stand by the comment that the extra cost for the R12 is cheaper in the LONG run than the other problems (poor cooling, leaks, short compressor life). <P>How much more is the R12? Even at 4 times the cost ($60/pound vs. $15/pound) the total cost penalty for R12 is less than a couple hundred bucks. No, I'm not rich either, but a couple hundred EXTRA bucks on top of the restoration or AC repair bill is not a big deal to make something "right".<P>Yeah, I know "lots" of people have switched to R134a. So what? "Lots" of people have problems with it, too. Just go to some of the automotive AC websites and read about all the woes of "average joes" that have converted their cars for the sake of saving a few bucks.<P>In closing, consider all the pros and cons and make an educated choice.

[jaxops]

This is a topic that has concerned a lot of us for some time now. I recently had my wife's 89 Crown Victoria SW AC overhauled, and we kept it R12. The conversion would have been another $4-500. I was worried about the R12 availablility for recharging, but so far, it has been there, but as stated you pay for it. <BR>I have also heard the problems with the R134, as well as a comment that it actually is more toxic than R12- but I have no 1st hand knowledge of that.<BR>I plan to replace the parts of my AC in my 70 Electra, and I will also keep it R12. I think that the RB might be a good alternative a few years out if it works well and avoids replacing the AC system for an R134 system.

[Guest]

I posted this to the ROA mailing list a few weeks back in response to the ongoing discussion of this issue. Note that it is somewhat specific to cars that use a STV to regulate cooling.<P>The early (63-5) Rivs used a Suction Throttling Valve, and not a POA valve. These systems adjust the outlet temperature by regulating the pressure in the evaporator (using the STV). The STV is adjustable, so it will handle the different operating pressures of R12 and R134a.<P>The problem with the STV is that they are vacuum operated (via the vacuum modulator attached to the temperature slider), and a) the diaphragms tend to go bad, and are expensive to replace. Luckily, the failure mode in the Riv systems is full cooling; in the full-size cars a bad diaphragm means minimum cooling.<P>If you're mulling a change to R134a, consider this: you can retrofit for well under the cost of a full freon charge. The worst part of the change is draining the compressor and replacing the mineral oil (incompatible with R12) with ester oil. This will only cost you $5 and some time, and the ester oil will work with R12 if you decide to switch back.<P>To make the change:<BR>- Replace compressor oil.<BR>- Install new ports for R134a fittings.<BR>- If your system hasn't been working for some time, replace the receiver/drier. You'll want to do this even if you're sticking with R12.<BR>- Evacuate system.<BR>- Install 75% of a full load of R134a (if your system uses 4# of R12, start with 3# of R134a).<BR>- Run your engine @ 2000 RPM, full A/C, with an auxiliary fan blowing across the condenser.<BR>- Add R134a 1 oz. at a time until you reach max cooling at the outlets (stick a thermometer in a vent). When the temperature starts to go up, remove what you just added.<BR>- Adjust the STV (loosen the lock nut and turn it in/out) to get an evaporator pressure of 18-23 psi on an 85 degree day.<P>NOTE: you will see bubbles in your receiver/drier with a full charge of R134a. This is normal.<P>Properly installed, this should get you to within 3-4 degrees of an R12 system. When you consider the original cooling specs, that's compatible with (or better) than some new cars. Of course, you will benefit greatly from a fan shroud and an operational fan clutch.<P>There are also rumors that R134a is more likely to leak through hoses due to its different molecular composition. I don't know if that's true or not, but there are two countering arguments:<BR>- the hoses are so thick that, while technically correct, it's not a practical issue<BR>- even if it does leak, it's a slow leak, you can replace a lot of R134a for the price of new hoses. It's like replacing your main seals to stop a slow drip when oil's .69 a quart.<P>Free advice (you get what you pay for): if your system works now, stick with R12. If it doesn't, make the low budget switch to R134a.

[NTX5467]

Konga Man's comments are accurate and go along with what I've seen in many other places. <P>The issue with the hoses is a "try it and see" thing. Seasoned hoses on an R12 system allegedly are fine, but if you change just the hose material on your existing barbed fittings, the barbs can probably puncture the new barrier hose and render it worse than what you started with so beadlock items are needed. Not to mention the type of clamps and how they are applied. I found that tidbit on a website <A HREF="http://www.aircondition.com." TARGET=_blank>www.aircondition.com.</A> <P>As for the butane mixes and such, yep, you can use them but I hope you don't run into me, cause a wreck and puncture your a/c lines in the process or the vehicle catches fire. Or in a single car wreck. Agreed, gas and other things in the car are explosive, but "gas" explodes, not liquid. R12 is flamable too, but not like butane or similar.<P>Also, there is a Variable Orifice Valve mentioned and linked to on the <A HREF="http://www.aircondition.com" TARGET=_blank>www.aircondition.com</A> site. It's available from NAPA and other places (listed on the link).<P>Lots of information on that site with two message boards--one of which seemed to be dominated by the propane/butane advocates.<P>As for R12, that issue's dead. You get the same penalty for bringing across the border as for illegal weapons and other controlled substances, which seems somewhat questionable but is a legacy of the Clinton/Reno years. There was also word of the bootleg R12 being more corrosive than the previous North American R12, but that could have been rumors.<P>The key issues with R134a are the amount of charge and type of oil. Maybe a few other minor tweaks. If the cooling decreases in city trafffic or at low speeds, an aux fan in front may be needed plus a fan shround on the older models without them. Most any new or reman compressor is now set up to handle either R12 or R134a, just add the correct oil. The old A6 should be fine as is and the newer "larger" R4s are what GM used prior to the current compressors.<P>The issue of originality might be debated at some time in the future, but if you want to drive the car and such I don't see what the big deal is. I know, if it came with R12 it should have R12 in it, but that option is fast going away--at any cost.<P>Key thing is to have a competent shop do the switch and follow industry guidelines. For the newer vehicles, there is some good information/recommendations in the back of the AC-Delco Air Conditioning parts book. Much of it can also be applied to some of the older vehicles.<P>Keep cool,<BR>NTX5467