rjtw

Thanks for the encouragement on the conversion but I will stay with R12 as long as that is the path of least resistance -- and I'm not saying that it is -- just saying that's where I will explore for now.

I called several local shops. The non-Porsche shops don't have R12. The Porsche shops for the most part refuse to even work on 928s. Why the lack of love? Sportech, on the other hand, was indeed willing to do the job (thank you Joe!!!) but quoted me nearly $600, and it's unclear if that even involves a purge or just a topping up. Ouch!

On the good news side, I'm beginning to see that topping up looks like a pretty simple job (at least so it appears in the video below) and something I can do quite inexpensively. For now, I'll pursue R12 locally, grab a gauge set and have at it. I'll report back.

Oh, one final question for the experts: What exactly is the low pressure fill port size? Is it 1/4" and will hoses like in this set fit?
Thanks!!!!!

Rob Edwards

The dimensions of threaded pipe fittings in the HVAC, hydraulics, plumbing, and various other trades are a complete and total nightmare of standards, conventions and skull and bones obfuscation, it feels like it's on purpose sometimes. I have no idea whether R12 fittings are 1/4", or where you'd verify that 1/4" measurement on the fitting (ID? OD? dunno), but the gauge set you linked for Amazon will by default work for R12. It has those two larger thread-on r134 quick release adapters so they can also be used on r134a systems.

rjtw

Thank you Rob!!!
Rick

The Forgotten On

R12 by default uses 1/4 inch connectors. I would personally take apart and replace the O rings and shraeder valves as they are long past it and probably leaking.

With the current cost of R12 it makes sense to do now before you have to refill it sooner than you should have too.

mj1pate

👍
it’s a situation where easy just means expensive

Babado

rjtw,
​​​​​​
​​​​​​I just took a look at my invoice, my A/C system was evacuated, recharged with r12 and dye and oil was added, I don't know what I spent, I had maintenance done to the tune $7.5k, parts were purchased separately from Roger another $3.5k, so I had quite a bit of preventative work done too.The system blew cold when I drove her home last July through the Sierra's.

I do trust Mark the owner mechanic, I asked him to do anything he saw that needed attention and the only thing he added was the power steering rack ( Roger) and a reference sensor that needed replacement after checking the fuel dampeners.

Joe

jcorenman

This whole refrigerant question is a moving target. R12 still works great, and is what our systems were designed for. But sometime around the mid-90's it was discovered that R12 causes damage to the ozone layer, so the world switched to R134. And sure enough, the ozone hole healed itself. R134 is not as efficient (lower specific heat or something like that) but works well in systems designed for it, and also in carefully-done retrofits.

But then it was discovered that R134 is a greenhouse gas, so that was replaced by R134a. And guess what? (You saw this coming, right?) Apparently, R134a is even worse for the environment. So (as of Jan '21) the world is changing again, to R1234yf, which also works well and is a lighter-weight molecule, which is much better for the environment. BUT (and you knew this was coming) it is also highly reactive, and attacks the lubricants and the parts that get lubricated. And it is much more costly. I am not making this stuff up, google "R12, R134, R134a, R1234yf".

There is no wrong answer. If your system is not leaking then all is good, whatever the stuff is. It is completely legal to continue buying and using R12 provided you have the EPA ticket noted above. Shops don't want to fool with it, so if you are having a shop do the work then go with their recommendation.

My personal choice was to spend the time learning (WSM is a good start but only a start), get the EPA license, track down a supply of R12, a gauge set, an electronic leak detector, a vacuum pump, an electronic vacuum gauge, and a recycle pump and tank, factory o-rings and new dryers, and then go through everything carefully. Not simple and not cheap, but less than many have paid for the retrofit to R134xxx.

Three things are important; (1) Don't waste your time raging at the sky for all the silly rules, it's all a matrix sim anyway. (2) Figure out what works for you, given your interest, skills, and budget; and (3) make sure that nothing leaks.

Cheers,

mj1pate

+1
The only things I can add 1) flush components and lines individually before the reseal and vacuum. The considerable goop that flushes out will give satisfaction to the effort and 2) doing all the poster mentions above is relevant for any R-whatever. I paid $33 for 36 oz R134a and it is fine for the mid-Atlantic. Use the refrigerant that instills confidence for cooling where you live.
+1 for item (3). Flush and reseal.