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:
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
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.
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
[size=+2]Do not convert it to R-134A[/size] 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 ou: I want ice cubes out of the vents, not a cool breeze!
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
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.
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:
Freeze 12 is just another 134 blend.......80% r-134 and 20% r-142. That don't sound like the real thing to me! ou:
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.
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.
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.