Discussion in 'The Big Chill' started by TSGS69400, Sep 9, 2007.
And lower pressures mean longer life for all the A/C components and a less likely chance of leaks.
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.
Of and over this summer we had some 100+ degree days, and it was blowing out 50 degree air, not bad in a vert.
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.
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.
It is only illegal to manufacture, import or vent R-12 in the USA. You can do anything else you want with it.
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.
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.
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.
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.