I'm glad I happened on this thread because my SD still has R-12 but I will need to refill. Where can I get auto frost?

Pete, try to stick with R-12 if at all possible. You're lucky, if you already have R-12 and the system doesn't leak much, you can just top it off.

AutoFrost (R-406b) is available from many online retailers but remember, you must evacuate your system & pull vacuum, then re-charge with R-406b. And if some leaks out, you can't top it off because it's a blend. That's why it's better to stick with R-12, unless you prefer the AutoFrost for other reasons (colder duct temps, you don't mind refilling & have the equipment, it's cheaper if you have multiple cars, etc)


HTH,

gsxr - thanks. I plan put in a rebuilt engine soon, and even though I think I can keep the system pressurized during this swap, I know it's low and the people I've gotten R12 from in the past can't get it cheaply anymore. Besides, I like to do it myself, and I'll probably have to sooner or later anyway. The colder temp is intriguing too; 55F duct temp still takes a while to cool @ 90F/90RH. If I used auto frost, (vac'd properly) and then needed to add later, would I have to vac again, or just empty and refill?

You can get the certification to buy R12 by spending $15 and 30 minutes or less at IMACA.

I bought the real deal R12 at Advance/Discount Auto Parts last summer for under $20 a can.

Yes, as Rick said, try other sources for R-12 first. 55F duct temp sounds high (warm) unless that's at max fan speed. I get duct temps of 40-45F continuously at freeway speeds, with R-12, at 105F/20RH. Read up on the AutoFrost website for info on duct temps (www.autofrost.com). Ooops, and it's R-406a, not R-406b, my bad. :eek: They also make a decent alternative for PAG/POE systems (CoolTop), but it's not as cheap as Duracool, IIRC.)

If you use 406a and some leaks out, you'd need to evacuate, then pull vacuum, then re-charge. It's not that hard but requires manifold gauges (~$100) and a vacuum pump ($200+), and perhaps an electronic scale if you are using tanks instead of little cans. If you learn how to service your own cars, and own several vehicles, buying the equipment can save a bundle in the long run compared to paying AC shops to do it for you! All I need is a vac pump, which I can borrow from my BIL's HVAC business when needed. :D :D

thanks for all the info! BTW, a DIY can easily get by with a compressor taken from an old fridge or window A/C unit. Just hook your gauge set up to the suction line. I did this with several vehicles many years ago.