50K car, what's your experience with the freon 12 system at this age? It's performing well now. Should I take the bite and have it converted now?

 

Lord no. If it ain't broke.....don't fix it. It will cost no more to convert when it finally quits. I had a R-12 system in a 1974 Dodge van that I bought new. In 2000 I finally got rid of it and the A/C still blew ice cold. Yours may work for another 10 years.

 

R12 Freon & the A/C compressor mineral oil will last almost indefinite as long as there are no major freon leaks.

R12 Freon takes 10,000 years time to break down to its basic element components.

Best freon ever made.
Very stable & very low boiling point.
Why old vehicles cool so nice with original R12 Freon yet today.

EPA said it was causing holes in the upper Ozone atmosphere & made it disappear from new vehicles back around 1994.

 

My vote is to leave it alone.

My '86 A/C worked just fine without maintenance for 20 years until I got a little carried away while cleaning out the junk between the condenser and the radiator and cracked a weld where the hoses connect to the condenser.

Still running R12.

 

My 90 is still R12 and has never been opened, blows colder than any new car I have.

 

I have close to 150k on my '93 and it still blows cold. No leaks? Then there's no problem and no benefit. Even if all the R12 leaks out, just diagnose the leak with UV dye, seal it, then buy a 12 oz. can of Freeze-12 refrigerant, and a 4 oz. can of Freeze-12 oil charge. It's compatible with R12 systems and you can buy it on eBay. My understanding is that (like R-134a) it's "more" o-zone friendly than R12, and currently does not require Section 609 certification for purchasing.

 

I always seem to run into leak-down on older systems that are driven seasonably. I haven't heard about Freeze 12, sounds too good to be true. I have an R12 Sanden compressor which I was going to try to retrofit to 134A in a street rod, so I can run 100% freeze 12?

 

I just finished converting mine over to 134a. It was having slow leak-down issues, and I've owned the car since new. It has <80k miles on it.

I sent the compressor to a friend who rebuilds them for a living. My seals inside were flat, and I was getting "some" leakage past there. I also had a bad Schrader valve that was affecting it. Changed out the rubber lines while I was at it...the A/C shop said they will leak after time, and 20 years is a little "time".

When I pulled the expansion valve I found shrapnel in the screen. Car has never had the A/C system cracked on it, and the compressor was fine when they opened it up. My only guess was the original compressor must have grenaded at the factory when they tested the systems out. Since I found the shrapnel I went ahead and put a new condenser.

I changed out everything, including flushing the evaporator. Basically, the system is all new now (except for the evaporator and the hard line from the evaporator inlet to the condenser outlet).

Next week they'll leak check the system and charge it with 134a. I'm choosing 134a because it is readily available. And with millions of cars running it, they will certainly have a replacement for it when the time comes to phase it out. I could go back with R12, but it makes no sense to do so at this stage. I've got a clean, new system ready for Freon...going in with R12 would be like re-wiring a network with Coax cable instead of CAT6.

If the system is good...leave it alone for sure. If it ain't broken, don't fix it. But once you crack it open...it's too easy to convert over. I can go to any Autozone and get 134a...I even have the gauges to refill it so once the shop leak checks it and gets it serviced I can keep it going indefinitely.

R12 is getting harder to find, and I've heard good AND bad about the Freeze12 solution. I'd rather just go with a known performer...less uncertainty that way.

 

Leaky shaft seals initiate wear on the shaft and will groove it if ignored. That's probably where the metal came from. It's best to mic the shaft before you continue with the compressor; otherwise, the seal will fail again. Unfortunately there are no specs (that I've ever been able to find) for an acceptable wear limit, so you look for consistency which is more than the discount auto parts rebuilders do. OP should look/monitor for oil on the hood above the compressor which is indicative of failure and the NIPPO compressor, though stout, has a reputation for eating up the shaft seal. As to converting, crap get a license at www.epatest.com and buy all the R12 you want.

 

If it works...leave it. There is absolutely zero benefit in converting a working system.

When there is a major failure that requires opening the system or major part replacement, plan on buying a new dryer/reciever, orifice for 134a, a qt of flush, and whatever piece broke or failed. Flush it all, change ALL O-rings, add new oil thats for 134a (r-12 compatable) and vac.

Its not difficult at all. Problem with conversions is that they often are not as efficient as the r-12 system. The 134a works ok, until the extremes like this past summer. Heat exchange is critical since the boiling point of 134a at various pressures/temps does not allow it to carry as much heat away as r-12 would.

Bottom line, leave it until you have to convert. No benefit in doing so before then.

 

He said there was no wear on the compressor...just the seals. They do hundreds of compressor rebuilds a month...and he took extra time on mine. Turned out the pressure relief valve was flaky and that got changed out before they let me take it home.

They told me mine was a "cherry" core...never touched before and no major issues with it. New seals and bearings, a relief valve and a rebuild on the clutch and I was out the door for $175

Should last me another 20 years now...

 

Technically, yes. Freeze-12 is compatible with R-12 refrigerant and oil, so it doesn't require a system flush. I wasn't aware of it until relatively recently either. But in my experience, it works just as well as R-12. My face can't feel the difference when the A/C's on full blast. Stalactites will eventually form on my nose either way..

I am 609 certified, but I didn't need to give my number to the outfit on eBay that I bought it from. Freeze-12 has no CFCs, so while it's still not environment friendly by any means, it won't do as much damage as R-12 (dichlorodifluoromethane), a chlorofluorocarbon by nature.

You're supposed to convert to R-134a fittings and slap on a conversion label in the process though, if you care about EPA compliance..

 

Freeze 12 is 80% R134 and compatible with nothing - dissimilar gasses are never compatible. Mix two together and you will effectively double operating pressures and that's in whatever course you took to get your license. If Freeze 12 doesn't say this in fine print somewhere, shame on them. Fortunately, accidents are rare as these old systems are bone dry when you start. I've seen a few horror stories on the a/c forums, but none here, though that's no reason not to keep it safe.

 

I misstated unintentionally. I guess that's what happens when you try to focus on four things at once. Anywho, Cr is correct. Mixing gases is a no-no. Freeze-12 is compatible with R-12 systems and R-12 lubricant. Evacuate the system from the low-side to 4 PSIG before refilling..

 

there are some other "blends" out there compatible with mineral oil used with R12. That's what Freeze12 is.
I think a vette AC needs to be at the top of it's game to use R134a. Most newer cars have bigger condensers than a vette.