[Mook]

Ok Guy's, I know this subject have been visited a million times but, I want a quick count on the pro's and con's on changing my system over to 134? I was set on changing it over but when I called the a/c repair shop said that they will change it over but it will not be as good as R12!!! What should I do. The system does not work now and I want to get it done next week!!!
How many votes for change over to 134 and how many against?

[Squidward]

R134 since you'll have to refurb all of your stuff anyways (orings, drier, hoses, flush, etc.).

[runningbwdog]

Hi,
The last time I checked R-12 was selling for about $40 per 12 oz can. Supply is limited.
With R-134A you may get less cooling but not much less, but you can buy it at any auto parts store, Wal Mart or Target. Squidward is right about replacing o-rings, drier, hoses and perhaps the expansion valve. Make sure that you get the right o-rings for R134. Once you have the sytem components all assembled, do a thorough pump down with a vacuum pump. Make sure it holds a vacuum for at least 2 hours. Overnight is better. If it won't hold a vacuum, it won't hold pressure and you will be constantly recharging it. Charge the system with the right amount of R134. Pressure on the low/charging side should be between 20-30 pounds. Buy one of those thermometers with the small dial face and long probe and put it in one of your A/C vents. You should get 40-42 degree air coming out on Max or High A/C.
Just my 2-cents worth.
Mike

[GTOWAGON]

I have done conversions from r 12 to r134 and it never gets as cold as when it has r12, on my wagon i went as far as replacing every component in the system which is a good idea due to the much higher presures with the r134, in addition to all o-rings the system nust be compleatly flushed and 134 compatible oil must be used, i also recomend having all the hoses replaced [this is due to the size of the 134 moleclues being much smaller in size than the 12 so they can leech out through the older type hose] the last thing you should do is add a cycling switch so the system dosen't blow up. After you have done this the best it will do is about 45 or so degrese out the vent with R134 VS. 35 out the vent with R12 dosent sound like much but boy does it make a difference, one good thing is that if you make all the changes and it works and does not leak then you can change it back to R12 and be prety much gauranteed it will work and not leak out any of the R12. RUNNINGBWDOG I don't know when you saw R12 freon at 40.00 per 12 oz but that is a fantastic deal!!!!!!! i have not seen anyone selling it for less than 100.00 per pound and that is if they can even get it.

[runningbwdog]

GTOWAGON,
You are right, it has been a while since I bought R-12. I have also used Freeze12 which is a less expensive substitute. A while back I did the certification course so that I could buy R-12 at auto parts stores. The price has steadily increased over time. I guess that R-12 smuggled accross the US-Mexico border is a real hot item. Maybe all of the illegals shoud bring five cans of R-12 with them when the make the crossing.
Mike

[JSAauto]

Runningbwdog...
I've actually taken a weekend off in Tiajuana just to visit and then pull into the Kragen auto part store and charge my A/C system while I was there!! LOL!!

R12 in the 12oz cans is about $6 a lb. in Mexico.

As far as the R12 vs R134a controversy. You can get the system down to 35 degrees if you do all this.

Replace the expansion valve to a R134a unit.... the ones for R12 are set differently than the ones for R12. If you have a POA system, they have new POA valves that are R134a compatible. The CCOT (cycling clutch orafice tube) systems using an orafice filter have problems with metering the the freon correctly. They have new orafice filters that are self metering especially for conversion. Having your manifold or any rubber hoses replaced with the new barrier hose is a nice upgrade also, but not totally nesscessary. Use a new dryer and new o-rings.

When charging, the low side is not the main issue. Depending on outside temps, you can easily overcharge the system using this method. Find out how many ounces of freon your system holds and start with 80% of that. Pay attention to your high side pressures. It would be nice if you could keep your high side pressures below 250. The low side should be around 30-38 lbs indicating good evaporator filling. I will hook my gauges to the system, tape them to the windshield and go for a drive and watch my pressures. See if they stay within the realm of what I described and your system is cold. If you high side does not want to behave, you can install a pusher fan on the condenser that is kicked on via a relay from the compressor hot wire. If you'll notice... most all the factory R134a systems have an electric fan on the condenser. Make sure your condenser is clean also. Blast it with a hose and make sure it's free of debris.

I actually installed a larger condenser on my 69 Firebird with this same technique. The A/C is so cold on a 105 degree day that you've got to turn it down.

[JSAauto]

PS.... the parts stores are not supposed to be selling you ANY kind of freon without a license. That is a Federal law. But I know Kragen does. So much for laws on the books.

[runningbwdog]

Hi,
I did the certification course, took the exam, sent in my money and got the certification ID card. Cost about $40.00 total. Most stores know and abide by the Federal and State laws about selling R-12.
Mike

[GTOWAGON]

Originally Posted by JSAauto

Runningbwdog...
I've actually taken a weekend off in Tiajuana just to visit and then pull into the Kragen auto part store and charge my A/C system while I was there!! LOL!!

R12 in the 12oz cans is about $6 a lb. in Mexico.

As far as the R12 vs R134a controversy. You can get the system down to 35 degrees if you do all this.

Replace the expansion valve to a R134a unit.... the ones for R12 are set differently than the ones for R12. If you have a POA system, they have new POA valves that are R134a compatible. The CCOT (cycling clutch orafice tube) systems using an orafice filter have problems with metering the the freon correctly. They have new orafice filters that are self metering especially for conversion. Having your manifold or any rubber hoses replaced with the new barrier hose is a nice upgrade also, but not totally nesscessary. Use a new dryer and new o-rings.

When charging, the low side is not the main issue. Depending on outside temps, you can easily overcharge the system using this method. Find out how many ounces of freon your system holds and start with 80% of that. Pay attention to your high side pressures. It would be nice if you could keep your high side pressures below 250. The low side should be around 30-38 lbs indicating good evaporator filling. I will hook my gauges to the system, tape them to the windshield and go for a drive and watch my pressures. See if they stay within the realm of what I described and your system is cold. If you high side does not want to behave, you can install a pusher fan on the condenser that is kicked on via a relay from the compressor hot wire. If you'll notice... most all the factory R134a systems have an electric fan on the condenser. Make sure your condenser is clean also. Blast it with a hose and make sure it's free of debris.

I actually installed a larger condenser on my 69 Firebird with this same technique. The A/C is so cold on a 105 degree day that you've got to turn it down.

I have done everything you mentioned in the gtowagon the only thing i have not done is add a pusher fan the best i have gotton is 42 degres at the vent i think i will try adding a fan and maby that will get me down the other 10 degres thanks

[engineer]

R-12 prices in Texas have come down since demand is not there any more and the supplies are sufficient to satisfy. I paid $29 per lb. in 30 lb jugs.

[Mook]

Where in the DC area is an a/c specialist that can do the job right? An hour or to drive would be worth it if the a/c shop is top flight!

[JSAauto]

GTOwagon?? You installed a larger than factory condenser also?? Like I said... the trick with R134a is keeping the high side pressure/temps at bay. If it's possible to keep the high side at 200 and the low side at around 32-38lbs at 2000 RPM's on say an 80 degree day, that would be awesome. Most of the time we have to undercharge the factory R12 setups that people don't want to pay and have a pusher fan or other custom trick done to.

Mook... if you look for an ASC (Automotive Service Councils) or ASA (Automotive Service Association) member, they're usually the better professionals. Ask if the owner or techs are members of IATN (Automotive Technicians Network) or STS (Service Technicians Society) and you will find guys that are part of an elite society in automotive technicians.

[GTOWAGON]

Not only went with a larger condenser i got a serpintine one i think the application was a 95 chevy truck. i am going to try the pusher fan and also will try the gauges on the windshield trick to see what the pressures are when driving

[Pitch 400]

Hotshot freon has about the same temp/press as R12.

[73ta]

I went with 134 but did'nt adjust my POA valve for it. Searching the web I found that it needs to be adjusted for a lower bypass pressure from the R12 setting. I found a company that cleans, adjusts and rebuilds them if necessary. They said that the majority of problems on converted systems with POA valves is the setting is set to high from the factory for R134, about 29 LBS verses R134 needs about 20 LBS. Although my system works alright with all new parts, it should get closer to an R12 systems temp with this adjustment.

[Mook]

Thanks, what does this POA look like?

[Dick Boneske]

You can buy 12 oz. cans of R12 Freon for $35-45. It is much cheaper to put R12 in an old system than converting to R134--also avoiding all the issues posted above--changing "O" rings, seals, expansion valve settings, etc. When you're all done converting to R134, you'll have a system that doesn't work quite as well as it did originally.

If you have a leak, it must be repaired anyhow. It doesn't cost more to fix a leak in an R12 system than R134 system.

As one of the posts above says, in some places R12 is coming down in price due to lessening demand.

As many of you know, R12 is sold in auto parts stores in Canada, just as it once was here. If you're concerned about the environment, fix the leaks before you recharge.

[JSAauto]

Dick...
The 12oz cans are illegal here in the USA. Only 30lb'ers or larger are sold anymore. If you can still find those 12oz cans, then consider yourself lucky.

Pitch400.... The problem with the R134a blends is the oil compatability. There are no oils that are guaranteed to work (circulate well) with R134a blends. And if they say they do... their full of B.S. The industry at large has only certified oils for automotive using R134a or R12.

We do a ton of conversions at the shop. They only thing we do is pull the system down with a vacuum pump. As long as we can hold 20" of vacuum for say 20 min.... then we charge they system with a few ounces PAG oil and R134a. Most of the cars we don't have problems with.... some we do. Some come back in a season needing a compressor. Oh well.....

[Dick Boneske]

JSAauto,

Yes, R12 or R134 is cannot be legally sold to or handled by non-licensed personnel in Wisconsin--and many other states. I have seen R134 for sale in Wisconsin within the past year at discount stores, in kits for conversion from R12 and in individual cans. R12 is always available on eBay. The two cases of 12 oz. cans I purchased in the early '90's should handle my needs for my two cars that use it. I have not seen or heard the proper procedure to dispose of or surrender R12 that individuals like me have in their possession.

Most repair shops now charge $500-$700 to evacuate and recharge auto air conditioning systems. I believe they have taken advantage of the lack of availability and laws restricting car owners from maintaining their own systems.

There are many neighborhoods in Colorado and California that prohibit car washing and oil changing by car owners. I'm sure that hasn't served to reduce car wash and oil change prices in those areas. It's too bad these kind of laws are getting to be more common. Those of us using this board will be in big trouble if this continues. Environmentalists are responsible for thinking up these laws and politicians are responsible for getting them passed to boost their popularity with the general public.

Sorry for the rant and getting off subject, but these issues are pertinent to our hobby.

[gtoformula]

Go up to the Search tab at the header and type in Clevenhagen. You will find a couple of posts. Send an email to Mr.Clevenhagen and he will sell you R12 without a CFC handlers license. The stuff he sells comes from Mexico (he is in San Diego), but it is made by DuPont.