You know I always thought those "oil charge" cans were just oil. Or did they make some with R12 and oil - and some with just oil? I'll be searching tomorrow because I know I have some R12 oil charges someplace...

 

It requires some R12 to carry the oil into the system. Only other way w/o discharging is to use an oil injector.

good luck

 

Do you have a particular make/model vacuum pump that you like and have had good results with?

 

I have a home-made pump from a refrigerator compressor.

Harbor Freight sells a small unit for < $100 that should be fine. Volume is not real important. You need to pull vacuum for some time to allow moisture to evaporate and escape. I run at least an hour before charging.

What did you decide on refill vs. retrofit?

good luck

 

Ok you asked.. Remember my priority is to get her A/C blowing cool quickly and inexpensively..

I've been doing a bit of reading. R12 cans are going for $35 or so each on eBay - and like you said, add an oil charge (another $25 or so plus some shipping). That's not horrible IF IT WORKS, but I sure don't wanna see the stuff just leak back out and find myself back at square one, with my wallet that much lighter...

Then I read about a bunch of people who used "Freeze-12" with supposedly very satisfactory results. Lots of happy campers. That got me curious.

It seems that "Freeze-12" is no longer made under that name. You can now purchase "Freeze" - and if you read the fine print on the can, it is R134a (?!!)

I dug a little more and somebody (who supposedly knows) told me that Freeze-12 was "99% R134a and the rest was a breath of hi pressure gas to help with oil return". If this is true, then the people who had good success with Freeze-12 were essentially mixing R134a with their R12. The process I read about had users add 1 can of stop-leak and 1 can of Freeze-12 Oil Shot. (So apparently the oils were mixed also)

I didn't read about anyone who destroyed their systems doing this though. So I'm thinking "Heck I can do that too. Just add R134a to the system, some stop leak and R134a oil and I'm good to go - and cheap too!."

Of course I always heard that mixing refrigerants was not a good idea (perhaps not legal?). But I also read that it WILL definitely work.

But then I thought.. if I'm gonna go this R134a route, why not just evacuate the system - check for leaks - replace o-rings, expansion valve and THEN charge it? (Another plus is that I may get to upgrade my vacuum pump )

One concern I have about converting is being able to thoroughly flush out all the old oil from the system. (That of course is not an issue if I recharge with R12)

So that's where I'm at. Is not being able to clean out the system thoroughly a concern? If not, then I'll probably go with R134a. If it is, then maybe I'll keep it R12...

 

I have not had opportunity for a retrofit, but have rebuilt a couple systems. I wanted to start from near-zero lubricant remaining before adding a new (different) lubricant.

I pop-blasted the condensor many times (pressurize w/ finger over outlet, and release). I pulled compressor and drained. I replaced receiver/drier (cheap part which should be replaced w/ a retrofit, R12 has wrong dessicant). Most of retained lubricant seemed to be in receiver/drier.

You can drain the evaporator as best you can upon removal. It is difficult to drain,.. I got nothing out. I've had no problems and added 8 oz of lubricant to my system when I installed. This is about twice the very difficult to determine spec amount.

good luck

 

Which begs the question... Why spend $25 on an old can of R12 oil charge? Why not instead spend that money on an oil injector?

There are different styles/brands out there. Do any of you guys have experience with oil injectors?

 

Makes sense if you plan other uses of oil injection. Cost will be at least twice what the oil/R12 can. Some issues w/ R134a vs. R12 fittings appears possible also.

good luck

 

Well I got a-hold of some R12 plus an oil-charge.

Oh one other thing I discovered was that the temperature control **** (on the dash) was broken. When you turned it, you weren't really doing anything because the inside part of the **** was disintegrated. So unbeknownst to me, there was some blending going on prior... so I remedied that.

After replacing the pressure switch connector (photo below), I hooked up my gauges. Well I hooked up the low side anyway.. I was surprised to discover that the high side fitting was a smaller size than the low side. My prior AC work has been on Fords, GM and Mopar - and I don't recall ever running into this. (Adapter needed?)

So I flew blind as far as the high side pressure goes. As the system stood, it was blowing 48 degree air. I added 1 12oz can of R12, then the oil charge, then another of R12.

Today it is 85 degrees here and I'm getting between 40 and 42 degree air from the vents. It's not the coldest system going, but it's colder than my R134a Toyota (44) !!

"After" photo of my pressure switch:

 

Low 40's is about as good as it get's w/ the Accords.

thanks for followup report.

good luck