What type of refrigerant??

[TSGS69400]

I'm back yall. I am wondering what type of refrigerant everyone reccomends using when I finally get around to putting the A/C back together.
I currently have all new parts for R-12 but my body man ( works for a heating and cooling bus. during day) says to fo R-134.
BTW. This is on a 1969 Olds 442 Convert currently being restored.:TU:

[alec296]

134 is fine to retrofit, just make sure your oil is correct for it and the right amount,retrofit fittings can be gotten from any parts store

[lsrx101]

R134a can work well in that system, but it has to be prepped correctly and the POA adjusted for best performance. No shortcuts.
Ideally you would use R12. It's what the system was designed for and that's what will work best. Again, the key is your system prep, no shortcuts.

[Electrajim]

Look for a "variable orifice tube" too if you go 134.
They may or may not make one for your application, but look around.
I have had successful conversions (12-134) on my 86 GN.

I stumbled across this link too http://buickperformance.com/ac.htm

Not _everybody_ likes 134 conversions. It's kinda like a carb. choice.
It's all in the tune.

ElectraJim

[Marco]

Do not convert it to R-134A

I made the mistake a couple years ago and I'm converting back to R12, which our cars are designed for.

Learn from my mistake :Dou:

I want ice cubes out of the vents, not a cool breeze!

[alec296]

i have done many conversions on 80s cars without problem
you will need to fill more than r12 filling specs
its all in the reading of the high and low pressure guages
ice cubes is possible just takes more work and might be a tad smaller

[carlivar]

Seems like Duracool and its equivalents (H-12a or whatever) is the way to go from what I've read.

[Electrajim]

I wonder how much that stuff is, and where you can get it. :confused:

ElectraJim

[carlivar]

http://www.foxtoolsupply.com/

Case of 12 cans of HC-12a is $70 + shipping.

According to my shop manual and the conversion to HC-12a weight, my 455 should require about 4 cans from empty.

[nailheadina67]

Best $70 I ever spent :beer

[BuickBuddy]

There is no subsitiute for the original..

http://www.freeze12.com/

88 degrees outside with the car sitting at idle. 185psi high side pressure and 28psi on the low side. 48 degree air. :bla:

http://users.ntplx.net/~gkitty/Temp.JPG

[nailheadina67]

There is no subsitiute for the original..

http://www.freeze12.com/



Freeze 12 is just another 134 blend.......80% r-134 and 20% r-142. That don't sound like the real thing to me! :Dou:

[lsrx101]

There is no subsitiute for the original..

http://www.freeze12.com/

88 degrees outside with the car sitting at idle. 185psi high side pressure and 28psi on the low side. 48 degree air. :bla:



Uummm, actually the "original" in this case would be R134a. Johnsons Freeze 12 is 80% R134a and 20% R142-b. The R134 does the cooling and the R142 carries the old mineral oil through the system.
You basically did a R134a conversion without knowing it. (Funny how Johnsons never mentions that little factoid). If you adjust the POA to drop the evaporator pressure about 5psi, you'll be down in the 30s.

Oops, Nailheadina67 beat me to it.

[BuickBuddy]

Freeze 12 is just another 134 blend.......80% r-134 and 20% r-142. That don't sound like the real thing to me! :Dou:

I didn't say real thing. I said it was the "original" first replacement for r-12. :rolleyes:

[carlivar]

http://users.ntplx.net/%7Egkitty/Temp.JPG

Where did you get that temp gauge?

[BuickBuddy]

It was on my brother's cart. :laugh:

http://users.ntplx.net/~gkitty/freeze12.JPG

[nailheadina67]

Heck, as long as it works. People buy that stuff and don't realize it's really just 134. :puzzled:

[lsrx101]

Heck, as long as it works. People buy that stuff and don't realize it's really just 134. :puzzled:

Yea, I don't have anything against FR-12, it works every bit as good as R134a.:laugh: . I just don't like the manufacturers sleazy marketing. They try real hard to keep that fact from being well known.

[copperheadgs1]

Maybe someone could do a side by side comparison between 134 original R12 and propane based R12a?

[nailheadina67]

Maybe someone could do a side by side comparison between 134 original R12 and propane based R12a?

All I have is this chart that compares the pressures of the different refrigerants.

I'm no scientist, but I think what this demonstrates is that hc12 has the lowest pressure at high temperatures. This translates into better cooling because it will keep the high side pressure lower which translates into less stress on your system and more efficient cooling.

If you look at the bottom of the chart, it shows that in low temperature, the pressure of HC12 is a small bit higher than the other two. This translates into being just very slightly colder at the evaporator where the pressure is around 28-32 PSI.

[carlivar]

I'm no scientist, but I think what this demonstrates is that hc12 has the lowest pressure at high temperatures. This translates into better cooling because it will keep the high side pressure lower which translates into less stress on your system and more efficient cooling.

And lower pressures mean longer life for all the A/C components and a less likely chance of leaks.

[red68skylarkcon]

I converted to 134 about 4 years ago. Check it every year when I get the car ready to show. But hasn't lost any charge. Had a leak and kept loose charge, found it and fixed it. Then converted to 134, the kit os like $40 at rural king I think. The kit has all the right stuff.

[red68skylarkcon]

Of and over this summer we had some 100+ degree days, and it was blowing out 50 degree air, not bad in a vert.

[Jim Cannon]

I totally rebuilt my '63 Riviera A/C system in Jan/Feb 2006 and charged it with R-12. Wow, it is great! It blows air in the mid- to upper-30s when it is over 90 degrees here in Houston. I replaced the condenser. I really think that helps keep the high side pressures down and improve cooling capacity.

The price of R-12 has really come down due to supply and demand, if you shop around. I paid about $10/lb (from eBay and Craig's List) and used about 6 lb total, all in.

We drove this car to Flagstaff AZ and back in late June, 2006 (very hot outside, over 100 in northern NM and AZ) and it kept us very comfortable. I have heard from many other 1st gen Riv owners that they were not happy with the cooling from R-134a.

Jim

[Buickfreak4ever]

So R12 is still allowed in the States? HEre in Europe it has become illegal te refill your car with it.

Besdies expensive retro fitting, you can also use R416a, it has the same cooling abilities as R134a and R12.

No changes have to be made to the old system other then that it has to be leak proof.

Costed me about 400 USD.

[70aqua_custom]

So R12 is still allowed in the States? HEre in Europe it has become illegal te refill your car with it.


It is only illegal to manufacture, import or vent R-12 in the USA. You can do anything else you want with it.

[71skylark3504v]

Uummm, actually the "original" in this case would be R134a. Johnsons Freeze 12 is 80% R134a and 20% R142-b. The R134 does the cooling and the R142 carries the old mineral oil through the system.
You basically did a R134a conversion without knowing it. (Funny how Johnsons never mentions that little factoid). If you adjust the POA to drop the evaporator pressure about 5psi, you'll be down in the 30s.

Oops, Nailheadina67 beat me to it.

How do you adjust the POA?

[lsrx101]

How do you adjust the POA?

Here's a good discussion that contains info on adjusting the POA. There is one with pics on that site, but I couldn't find it.
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=6974

It happens to be on a 71 Riv.

[71skylark3504v]

Here's a good discussion that contains info on adjusting the POA. There is one with pics on that site, but I couldn't find it.
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=6974

It happens to be on a 71 Riv.

Thanks for the link, but I could not find any specific info on where that screw it or what it involves to get to it.

[lsrx101]

Thanks for the link, but I could not find any specific info on where that screw it or what it involves to get to it.

Sorry, wrong link. There is a 7/32" screw inside the outlet port on the POA valve. You need th turn it 1/2 turn CCW.

[lsrx101]

Just to elaborate on the POA valve adjustment:
With R134a. you want to see the evaporator pressure (low side pressure) about 24-26 psi. with good airflow over the condenser. R12 was about 30-32 psi. The POA valve is calibrated to hold the evaporator pressure at 30-32psi.
GM always stated that the POA valve was not adjustable, it is what it is.

There IS an adjustment that will move the evaporator pressure downward as needed for R134a conversion.
To "properly" adjust the POA you need a setup with a pressure gauge, 60psi of air, and proper adapters. Check out www.autoacforum.com and do a search for POA if you need the howevers and whyfors. With a known good POA, the adjustment usually comes close to 1/2 turn CCW of the 7/32" screw in the outlet side of the valve for an R134a conversion.

Proper testing can dial the valve in much closer, but 1/2 turn during a DIY retrofit can make a huge difference in the end result.