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R-12 Air Cond. Servicing


GOOB

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Summer is around the corner and I am getting the "low refrigerant" message and my compressor is not kicking on so it is time for repair. I have a Chilton's Manual and my reading skills are pretty good. I am a U.S. Marine so I follow directions well. I consider myself to be "mechanically inclined" but I need some pointers on servicing my A/C for I have never done this before. Is this something I can tackle myself or should I take it to the pros (thieves) at the local Caddy dealer? Any safety matters that I should look out for?

Any helpful tips, pointers, suggestions will be appreciated.

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You can find R-12 and the charging hoses on ebay at a good price (by today's standards...). Otherwise, you'll need to find a shop that will top off the system for you.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I would get a factory service manual and just use the Chiltons for general problems. The Chiltons does not go into as much detail and too many years are crammed into it.

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1st Be sure if is R12 or not. If it was serviced after R134 it may have been changed over. If not, And it is still r12 I think you'd be well advised to just take it to a shop. If that is not in the budget, they do make some stuff to top it off that is R12 compatable. No kidding, wall mart.

Low side is the side that gets cold. On your car proabl;y right nearthe radiator fill tank.

You can get a R134 fill kit pretty easy.

It has instructions.

The conversion kit is like $20 and that includes the R134 and the fittings to change from R12 to R134 plus some oil. But I don't think it is a job to do it yourself unless ya have the equipment and the know how.

If all it needs is a top off, then top it off with a compatable product. Look for stickers that say what is in there. If it's converted there should be a 134 sticker. You can always tell by the fittings because you can't put 134 into a 12 fitting Visa versa.

DON"T overfill it by any means. A guage comes with the kit. Some have one built in on the can.

If you get a lot in and still no cold. Proably time to clean the system out real good and refill with 134A AKA as the "Conversion" Best left to the pros.

Because.

1st they will safely evacuate the system and put the R12 in a container.

2nd they will suck it down to like zero presure.

3rd they will and should totally clean the system. And I mean clean, get every drop of R12 oil and fluid out, it turns to snot in the system when it contacts R134, and snot can clog up they system and make it not work.

4th They will do a swap out of the dryer, good insurance at this point and will make the charge last for years. It's extra cash but well spent long run.

5th After they mess with that they will vaccume the system way down, the longer the better. I do mine at least 4 hours. (But I have a small pump)

6th they will shut off the system with the vaccume on it and see if it bleeds up. (Meaning it has a leak somewhere) If no bleed and system remains stable it's time to put one whopper of a charge on.

7th They start the car and slowly add in some oil, (Each car has a specified amout and a spacific type of oil, ya have to know what you are doing. This is a needed lubricant for the system, mostly the compressor. Too little and you will get cold air for a while and then hear your compressor fry, the belt will freeze up and car will stop.

8th they will put in the right amount od R134 and then top it off to the high side of the chart.

If they do it all right, your car will be so cold inside, you'll have to put your coke in the cooler to keep it from freezing!

Semper fi!

Old 4th Force Recon, Pearl Harbor, Hi

MC

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Semper Fi , Goob.

Thank you for your service to our country.

Before you spend any money, unplug and replug all the electrical connectors along the A/C lines. Sometimes a dirty connector will throw bad code. It's free and will take five minutes. Worked for me.

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Okay, got stuck in traffic yesterday waiting on a bridge opening...black car + black leather + no A/C + no airflow = time to fix the A/C.

I really need your help with this decision. I am thinking about converting over to R134A but I have heard mixed reviews. I am willing to pay for the R12 if that is the best for my car. I have heard that by converting over, I will loose some "coolness". I converted my old 91 Seville and didn't notice any problems.

So, which way should I go? Somebody sell me a product!

Thanx

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I just had my A/C retrofitted in my 92 Chevy Pick-up. I also had the compressor seals changed. When I first bought my truck back 4 years ago the air never worked and I topped it up with Duracool (cheap R-12 knock off I bought at a local parts store) and it made the air cool, but not ice cold. If I went on a two hour drive, after about hour it would cool off in the cab on High and Max. I was working at a GM dealer here and had a mechanic do it over the lunch hour. Retail on the fittings is $15.00 each (x2), R-134a costs roughly $15.00 a pound (took two pounds), compressor seals were $30, and I paid the mechanic $50 cash for his work. So for a little over $140 I have ice cold air. If I have any problems with A/C on any other cars, I'm going to convert them too. Bring on the HEAT!!! :P

Spence

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I believe I remember Guru saying that R134a is only slightly less efficient than R12. So much so that it takes instrumentation to tell the difference. That being the case you need to weight the difference in the price of R12 with the price of a conversion and how long you will have the car, and wether or not you think you may need to top off again. FWIW I just saw R134a at Napa for $5-$6 per can.

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I think you should have it converted. It's just going to get harder to find any r12 as time goes on. My father had his Toyota Previa converted over and it worked fine.

It will cost much more to properly retrofit a vehicle to R-134a vs. staying with R-12. R-12 is still available - just not at the local parts stores. You just need to have EPA 609 certification to buy it. You can take the test online for $20.

My advice is to stay with R-12.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Yea the mechanic said something like that. The air compressor cuts out a bit early because of a switch that screws into the evaporator. He said there is a new switch you can buy that tells the compressor to stay on for about 10-15 seconds longer than the stock R-12 one. He said the switch would be cheap (under $30). I am going to wait until it is 100 degrees to see how it works and then see if I will change it.

Spence

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I am curious to know what the concenses is on using a R12 substitute(freeze 12 etc.). I found that the freeze 12 is cheap, but does it work?

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Freeze 12 WORKS GREAT....have used it for several years now on many cars and trucks.... have never had a problem. ya gotta understand tho...if your system is screwed up (ie: leak, bad compressor, blown air dryer, ect.) Its not going to work. If on the other hand your system has a slow leak, and each spring you need to add a can to top it off its the only way to go. On several cars that have had no R12 in them ( I repaired the leak) I have pumped the system down and have refilled it with only Freeze 12. They all now... Blows Ice Cubes. ;)

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Freeze 12 is 80% R-134a and 20% R-142b. As you may know, R-134a is not miscible at all in mineral oil, much the same situation as oil and water (non-polar and polar). R-142b is only weakly miscible, therefore, the Freeze 12 blend does not circulate mineral oil very well. Depending on the suction line design and compressor location, the system may work for some time, however, I would say that compressor life will be affected negatively in the long run. Another point to consider is the addition of 20% R-142b changes the pressure-temperature relationship. On systems that control the compressor based on low-side pressure, vent discharge temperatures will be noticeably higher.

I think it would be best to stick with R-12, or use a drop-in substitute having similar pressure-temperature characteristics and excellent miscibility in mineral oil, such as R-406a or a hydrocarbon blend like Duracool (roughly 60% propane, 40% isobutane).

___________________________________________________

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Make darn sure you purge the line of air, before you introduce freon into the system. If you do not have adequate pressure, i.e., the system is very low, you are going to have to use a vaccuum pump. Without decent line pressure, you will introduce air immediately. If you just need to "add a can" per se, the initial hookup will push freon out, into the line. You can then bleed the line by simply backing off the fitting, and then re-tight it. You should hear something escape. You can then open up the valve to charge the system. Air mixed with freon will create a gas that will eat away at the seals of your system. A leak would eventually present itself.

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Hey Styes,

Enlighten me a bit about vacuuming they system for future reference. Can it be done with a hand held vaccum pump? I assume you must need some type of adapter to fit the shreader valve? How much vacuum?

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Larry,

The vacuum pump has an oil reservoir and is driven by an electric motor. I suppose in theory, it would be possible to vacuum down a system with a handheld mity-vac but you'd have carple-tunnel before you were done...

When the system is totally discharged, you need to evacuate it with a vacuum pump. By creating a vacuum in the system, the boiling point of water is lowered enough to be vaporized at room temperature and sucked out of the system by the vacuum pump. Evacuation is only required when the system has lost the refrigerant charge. If it is just low on refrigerant, it can be topped off without a problem. As Styes says, it is best to burp the air out of the charging hose before charging.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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When vacuuming the system, the low pressure gage will show 29" of vacuum until the valves on the charging manifold are close and the pump is turned off. The vacuum reading will lose 1" of vacuum for every 1000 feet above sea level. If you were at 2000 feet elevation, the gage would drop to 27" when the charging manifold valves are closed and the vacuum pump is turned off.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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When the system is totally discharged, you need to evacuate it with a vacuum pump. By creating a vacuum in the system, the boiling point of water is lowered enough to be vaporized at room temperature and sucked out of the system by the vacuum pump.

Although water will boil at room temperature under a 28.9" Hg vacuum, evaporation (water and other contaminants) will remove heat from the system. The colder everything gets, the higher the vacuum required to reach the boiling point. The ability to hold a 29.82" Hg or higher (1000 microns or lower, 1 atmosphere = 760,000 microns) vacuum ensures the refrigerant system is dry and reasonably tight. A manifold gauge set is useless for measuring vacuum in this range; a micron gauge is required. A tight, dry, original system may take as little as 10 minutes to reach 700 microns. A wet one could take over 3 hours.

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  • 1 year later...

Well, coming to work yesterday, I once again got the "low refrigerant" warning. The charge of R-12 I got last year lasted a year almost to the day. Looks like I have a leak. Thinking about going ahead with the conversion this time around. Anyone have a price estimate on repair?

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Well, coming to work yesterday, I once again got the "low refrigerant" warning. The charge of R-12 I got last year lasted a year almost to the day. Looks like I have a leak. Thinking about going ahead with the conversion this time around. Anyone have a price estimate on repair?

Just have the leak repaired and stay with R-12. The price of R-134a is skyrocketing. In about a month, R-134a will be the same cost as R-12 due to a manufacturing capacity issue.

I bought a 30 lb. cylinder of R-134a last year for $57. Now it's $300-$350 with prices expected to be $400-$500 by the peak demand season. You can buy 30lb cylinders of R-12 on ebay for $500 or so....

I was in an auto parts store yesterday afternoon and noticed that 12 oz cans of R-134a were $15.99......

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Another alternative is Dura-cool, R-134 doesn't cool nearly as good as r-12 and the dura-cool cools a little bit more than r-12. It's what we are running in my brothers Catalina and it frosts the vents (really). Another thing about it is they(duracool) also sells a thing that converts the water in the system to oil.

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Another thing about it is they(duracool) also sells a thing that converts the water in the system to oil.

What???? How does water get converted to oil??? You do not want ANY moisture inside an A/C system - period....

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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