72 BB air conditioning, R134 upgrade

[Randy Krohn]

My A/C compressor is running OK, but the line going to the heater box is barely cool. I suspect a slow leak, as it was OK last summer.

Has anyone out there upgraded an R12 system to R134? Comments?

My experience with other cars is that it's cheaper (and easier in the long run) to upgrade to R134 instead of messing around with R12 repairs/refills...

Thanks!

[Michael M.]

Re: 72 BB air conditioning, R134 upgrade

I too have a '72 BB w/ AC. I'm restoring it now and am planning to try a product called Freeze 12. Supposedly, it replaces R/12 w/o the R134 conversion.

[Santo S.]

Re: 72 BB air conditioning, R134 upgrade

Hi,
I changed my system on a 71 small block car to 134a three (3) years ago,
I had to change the compressor because it locked up, so I decided to go with 134a
I added a nos POA valve and dryer changed the oil in the compressor to 134, evacuated
the system and charged it. It worked better with 134 than it ever did with freon 12

[Dick W.]

Re: 72 BB air conditioning, R134 upgrade

I did a '72 5-6 years ago with good results. I did change the condenser, after all one 25+ years old would need to be replaced whether going back with R-12 or R134. Drained the compressor, replaced the drier, flushed the system, added oil and the proper amount of R-134. 39 degrees right duct temperature. Very comfortable road tour car now.

[Tom Freeman]

Re: 72 BB air conditioning, R134 upgrade

"Has anyone out there upgraded an R12 system to R134?" I think you mean downgrade

If the system is right, and it should be before you put anything in it, then a charge should last for years. No reason for it to leak out. So my feeling is to get the system right, then do a charge of R12. Cost more but spread out over several years it is only a couple of bucks a year.

tom...

[Tom Freeman]

Re: 72 BB air conditioning, R134 upgrade

"I'm restoring it now and am planning to try a product called Freeze 12"

Freeze 12 is 80% HFC-134a and 20% HCFC-142b. So why not go with 100% 134a?

[Geoff C.]

????????? R134 upgrade

Gentlemen:

I agree R134 is not an upgrade for a c2 or c3. It's a cheaper cooling agent, however it will not solve leaks; it will not solve clogged evaporator or condensor fins and it will not solve low volume airflow from the ductwork.
Changing over to R134 may not even be cooler. Everything I read says it does not cool an original equipped R12 better than R12 does. It's only cheaper. And I suppose if you have a leak, it will merely leak more freely - if the rumor that the molecule of R134 is smaller than R12 is - if that size difference is actually true.

I have one car with a supposed R134 conversion, but that AC never worked from the day I test drove the car, so I cannot truthfully says it's a actually warmer or cooler. But it's a convertible so I have not had the AC working.

Geoffrey Coenen

PS If you go with R134, also try the conversion to longer blower motors with hand hewn spacers - they will no doubt work well together.