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FastWoman

Conversion to Freeze-12

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Hi all,

I have a moderate leak in my original R12 A/C (1978). It needs to be juiced up every year to cool. This year, again, it's only cooling just a bit. I exhausted the last can of my R12 hoard a couple of years ago, and last year's professional topping-off set me back $150. I think it's time to lose the R12, fix the leak, and recharge with Freeze-12.

I see in the FSM that the system takes 1.5 - 2 lb of freon, fully charged. I believe my topping off amounted to about a pound of freon, so would this imply that I have about 1/2 to 1 lb of freon in the system? Would that amount of freon give me a marginal cooling?

Then what to do with the R12? It's illegal to vent it. Will service centers reclaim my R12, and if so, would they actually want to charge me to take this precious substance from me?

I understand Freeze-12 is compatible with the mineral oil used to lubricate an R12 system, but it not compatible with the R12. Thus my plan is to evacuate and recharge with the Freeze-12. With this in mind, how do I determine how much oil is in the system and how much oil to add, if any?

Also, is there anything else I need to change out, other than the freon?

Thanks for any advice!

Sarah

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..... and..... no sooner than I posted this and gone out to the garage to look in the FSM again, I FOUND 4 MORE LB OF R12!! Soooo... never mind. I swear, guys, I had spent the past few hours looking for any remaining cans. :rolleyes:

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My 77 has a slow leak. I put in freeze 12 last year, by itself and then later put in some freeze 12 stop leak. Once again this year it is low, but still cools somewhat, so I have no idea how much I have lost. When L28 goes and the turbo motor goes in I am going to replace all the o rings and lines in the engine bay and also paint the engine bay. If that does not fix it, I suppose it is behind the dash.

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Fastwoman if i had 4lb of r-12 around i would tear the system down and find that leak, then fix it permanently. If its fixed correctly that R12 could last another 10 years vs 2 years of refilling a leaky system.

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Kurby, that's probably a better idea.

Here's the thing: No sooner did I announce that I found 4 lb of R12 than my R12 can tap broke. :tapemouth:mad::tapemouth I can't understand how it happened. It's made from the very finest Taiwanese pot metal! Fortunately there were no R12 casualties. That said, my precious R12 is now worth about what Freeze 12 costs -- about $20 a can on ebay.

Anyway, there are can taps on Ebay, so I guess I'll be ordering one. I had so hoped to have cold air today. Ah well...

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3-diameter can side tap, $25 shipped, eBay. Thank gawd.

I'll be taking your advice, Kurby. It only makes sense to find the leak before committing more R12.

I still wonder how to determine how much oil I have in my system without pulling the compressor and draining it. Is that the only way?

Edited by FastWoman

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FastWoman - Here is what I would do. I would get a little Florescent AC Dye and get that into your system, then let run for a bit to circulate the dye. Hit everything with a LED Blacklight Lamp to expose any leaks. There are little LED Blacklight lamps avail at the autoparts store (good to have in the toolbox). With the cost of R12 Refrigerant, really all refrigerant - AND your time, it makes sense to identify where the leak is prior to dumping more R12 and $$$ into the effort. Check the Condenser, Compressor(behind clutch), and Evaporator, with the dye it will be very obvious!

I believe that it would be a good time to start lining up modern replacement components.

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Sounds like a plan, Andrew. Do you think a few trips around town would be enough for the dye to reveal the leak(s), or would I have to leave it in there for much longer than that?

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A few trips around the block might actually be too much. The dye works pretty quickly so as long as the compressor is engaged you should be looking for the leak.

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Tip: the refrigerant is actually more heavy than air so you will find the dye under the leak, not over. make sure to check inside the dash too, you could be leaking at the evaporator

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the dye colors the refrigerant so when it leaks out you can see it with the UV light. so yes you are looking for a leaking gas, not an oil

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Sorry Sarah, just now seeing the responses, I believe that KurbyCar32 hit it spot on. After you repair whatever is exposed by the dye, make sure to clean the area with Brake Cleaner and then something soapy to remove the dye -This way you will get a 'Clean Slate' for future leak detection.

There is also the possibility of borrowing a Halogen Leak Detector to check for leaks. I say borrow, because these dudes are mucho $$$ to buy for the casual user. Just thinkin.....

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There is also the possibility of borrowing a Halogen Leak Detector to check for leaks. I say borrow, because these dudes are mucho $$$ to buy for the casual user. Just thinkin.....

It might be possible to borrow one (with a big deposit) from a local auto parts store. I'll check into it.

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is there oil around the front of your a/c compressor? if so, the front seal is leaking. another place that leaks is the high and low side charge ports.

and lastly the rubber hoses can leak but those first 2 are the most common places to leak. you cannot just keep filling with freon though. whenever

freon escapes it takes oil with it so you're probably running low on oil. ive replaced valve cores before and they've still leaked. probably the seat is

bad but not sure. maybe just cheapo replacements. one quick fix is to get some r134 charge port fittings and remove the cores if they have any.

then find a bolt that will thread into the top of the r134 fitting, most are threaded on the inside. i use teflon tape on the bolt thread too. then i screw the retrofit fitting over the top of my r12 charge ports and it seals pretty good. start the car and test with soap and water from a spray bottle. at the very least put a few oz. of oil in before you top off.

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Thanks, hr369! I'll look for those trouble spots. My one known leak is on the high side connection to the evaporator assembly at the firewall. It's a bit oily there. The compressor looks pretty clean. Adding oil sounds prudent.

I'm afraid I've been slow to get to this repair. Perhaps I'll be able to locate that "round tuit" when the weather gets warmer.

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Update: I finally got more motivated with the warm weather, and my A/C is blowing cold again. :)

I found the leak. The flare fitting on the high side of the evaporator coil (at the firewall) had gotten loose, so I tightened it (and also the low-side fitting).

Now here's a clever way to reclaim your freon without a fancy freon reclaiming machine. You'll need an empty freon can that you've saved back: First, hook up your empty can to the center (yellow) hose of your manifold. Then evacuate it through either the high or low side line. Close your valves, and then hook up your H and L lines to the A/C. Purge the air from the lines at the manifold fitting. Then tighten the fittings, and open the valves. Now put the empty freon can in an ice bath to lower the vapor pressure. What's left of your freon will slowly condense into the can. This will take quite a while, but the operating principle is the same as that of a heat pipe. When you're finished, there will be no liquid freon left in your system. Obviously this won't work if you start with more than a pound of freon in your system.

So with an empty system, I then evacuated, let stand for 30 min, and observed no change in vacuum. I then introduced 2 oz of mineral oil and dye. Here's some helpful info in that regard:

R12 refrigerant oil (rather viscous, dehydrated mineral oil) is REALLY hard to find. There are mail order sources, and I suppose you could buy it with the requisite licenses at a refrigeration company, but there's still one source where everyday people can just go and buy the stuff locally -- NAPA. It's a stock item there. When I asked the guy at the counter for a bottle of the stuff, he said he didn't think he would have any, but he went into the back and surfaced with a dusty 1 qt. white plastic bottle that had turned yellow over the years. The total with tax was $10.15.

Getting it into the system can also be challenging. In the good old days, we'd just buy a 2 oz can of the oil, loaded with a bit of R12, and shoot it in. You can do that with 134a, but not with R12. Our stuff just comes in a bottle. So what you do is use one of those precious empty freon cans that you've saves, patting yourself on the back that you're the sort of pack rat who never throws anything out. You cut it in half, making a cup with a fitting on the bottom. Pour in your oil, and suck it right into the evacuated system. The easiest way to do this is to evacuate via a hose directly from the pump to the low side. Then connect the high side hose to the manifold and the yellow line to the can. BTW, it flows slowly into the vacuum, being rather viscous. Now change around the fittings, evacuate again via the yellow line, and charge the system. You'll get just a bit of oil back into the vacuum pump. (Mine fluoresces yellow now!) FAIW, I think there's such thing as an oil syringe, but I couldn't find one.

Anyway, with luck my system is now tight and will not leak my precious R12. And I'll be cruising the Colonial Parkway in cooooool comfort. :cool:

Edited by FastWoman

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Congrats! That is great news! Ten years ago I bought a AC Oil Injector that allows just about any liquid to be added to the AC system. The tool holds approx. 2 oz and a weee bit of dye.

post-7312-14150818950044_thumb.jpg

These cost about $30

BTW: I am jealous about your cruising the Colonial Parkway....nice.

Edited by ZCurves

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Yeah, I could have used one of those! Harbor Freight? (I didn't look there.)

The Colonial Parkway is great, but so are parts of Texas. Brenham in the springtime is one of my favorite drives. One particular drive through the Brenham area was the closest thing I've ever had to a religious experience. :)

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Sarah, are you talking about ester oil? If so, it's really not that dificult to find. I get mine from Johnstone Supply. All they do is HVAC.

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Steve, I mean the mineral oil. As I understand (note: I'm no A/C expert. I've just done some reading...) the ester oil is considered compatible with residual mineral oil when doing a 134a conversion, and it's of course very easy to find. However, that doesn't mean that the ester oil gets along optimally with the R12. I've been told technicians do add ester oil to R12 systems, but I simply erred on the side of caution and used the original variety of mineral oil. It was probably unnecessary to do so, but I always prefer using the original stuff, rather than something that's compatible with the original stuff.

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