Replaced R-12 with Freeze-12 today

[rrubel]

Had my mechanic suck out all remaining R-12 (3 oz, he said) and today replaced as many seals as I could (the ones on the back of the compressor are VERY non-standard) and added Freeze-12 and oil. Odd thing - normal charge is supposedly 2-2.25 lbs for our cars; I put in only 26 oz +/- of Freeze-12 and got 35 psi with the compressor on. Freeze-12 says it takes about 10% less than normal to get the same cool, but that'd still be 29-34 oz. of refrigerant.

Anyway, it blows cold right now. We'll see if it stays... all I need it to do is last for the trip to Carlisle; anything more is a plus, really.
[RICHR]

 

[nyernga]

Had my mechanic suck out all remaining R-12 (3 oz, he said) and today replaced as many seals as I could (the ones on the back of the compressor are VERY non-standard) and added Freeze-12 and oil. Odd thing - normal charge is supposedly 2-2.25 lbs for our cars; I put in only 26 oz +/- of Freeze-12 and got 35 psi with the compressor on. Freeze-12 says it takes about 10% less than normal to get the same cool, but that'd still be 29-34 oz. of refrigerant.
[RICHR]

He did pull a good vacum right Rich? It's possible there may still be non condensibles in the system causing the higher pressure reading with less refrigerant. Sometimes you have to do whats called a double or triple vacum to get below 500 microns and stay there.

Len

 

[Bill Heygster]

Gordon Killebrew swears by that stuff. If you have any questions he'll probably be glad to help you out. His tent at Carlisle is usually across form the GM tent

 

[rrubel]

Huh. Len, I didn't ask about what else he did other than draining the R-12. I'll ask tomorrow. Hate to sound like a moron, but what did you mean by getting below 500 microns? I thought a micron was a size measurement...

Bill, if Gordon swears by it, that's good enough for me. I worship that guy...
[RICHR]

 

[wishuwerehere82]

micron (µ) an informal unit of pressure widely used in vacuum technology. In this use, a micron is a micron of mercury, that is, 0.001 mm Hg or approximately 1.333 microbars (µbar or µb) or 133.3 millipascals (mPa). For all practical purposes, 1 micron is identical to 1 millitorr (mTorr).

In this application, 500 u is a very low vacuum intended to boil off all water in the system at room temperature.

 

[geekinavette]

Huh. Len, I didn't ask about what else he did other than draining the R-12. I'll ask tomorrow. Hate to sound like a moron, but what did you mean by getting below 500 microns? I thought a micron was a size measurement...

Bill, if Gordon swears by it, that's good enough for me. I worship that guy...
[RICHR]

My first thought too...never heard of a micron as a unit of measure of pressure. To me a micron is a "micro-meter"...or 0.000001 meter.

Learn something new every day!

I used Envirosafe in mine...works quite well. Factory volume was 2.75lbs of R12...Envirosafe equivalent is 14oz. Nice part is it is not necessary to pull a vacuum.

Bill

 

[Moonunit 451]

Freeze12 is a drop in from what I understand. You didn't even need to draw the system down. 2nd summer on mine and it's all good Rich You'll be fine.

 

[Robertwav1]

Moonunit that's my understanding also, a drop in replacement. I always use 12. A vacuum is not necessary to remove non-condensibles if the system had any gas in it to begin with. In fact, if there are any minute leaks in the system even the non-reliable seal in the compressor, you can draw air in with a deep vacuum. I seldom do this unless a system is open or completely empty. Just my opinion.

 

[Bill Heygster]

Hopefully a simple answer
An automotive refrigeration or cooling system is a sealed system. Therefore if it is low on gas it went somewhere - It had to leak out. It doesn't evaporate. If there is a chance of gas leaking out there is a chance of something getting in. You can always "add some freon" to a cooling system that is low and get results to a point. Generally though once gas leaks it will continue to leak until you repair the leak. In an auto system it's usually seals or connections that leak. To repair a leak you must drain the system, repair the leak(s) and then put the system in a vacuum (1 ) to remove all the non condensable gases and (2) to make certain the sytem is tight. You can get as techical as you like but if the system holds a vacuum for a periosd of time it's tight and ready to refill.
This doesn't matter if you are using Freon or Freeze 12. If your system is low the gas went somewhere and until you find the leak and fix it you really haven't fixed the problem.

Agree with your opinion of Gordon. We went to his school last year in Tennesee.

 

[Jack]

... added Freeze-12 and oil. Odd thing - normal charge is supposedly 2-2.25 lbs for our cars; I put in only 26 oz +/- of Freeze-12 and got 35 psi with the compressor on. Freeze-12 says it takes about 10% less than normal to get the same cool, but that'd still be 29-34 oz. of refrigerant.

What about the old oil? ... it occupies a volume ... as does the new oil.

Also, my 97 GMC pu had a HT6 Harrison ac comp ... HT6 has lousy rep for leaking where the end caps bolt to housing ... mine no exception. Recently got a retrofit kit that included a Ford type FS10 Visteon ac comp ... these have a much better rep for durability & performance. Bolted right up to GM bracket ... hoses fit exact ... clutch/serp pulley fit exact. Included a short pigtail to adapt elec plug from ford to gm, new hose seal washers and was filled w/ new oil ... all I had to do was swap out the pressure switch in back ... easy! All brand new comp, clutch & pulley was about $160 from Carolinas Auto Supply House of Charlotte NC. Old comp had not torn up ... just leaked ... no new orifice tube needed. Installed w/ new dryer-accumulator (~$18) ... Pulled a vac, charged w/ 134 ... Works like a champ!
JACK:gap

 

[Robertwav1]

Hopefully a simple answer
An automotive refrigeration or cooling system is a sealed system. Therefore if it is low on gas it went somewhere - It had to leak out. It doesn't evaporate. If there is a chance of gas leaking out there is a chance of something getting in. You can always "add some freon" to a cooling system that is low and get results to a point. Generally though once gas leaks it will continue to leak until you repair the leak. In an auto system it's usually seals or connections that leak. To repair a leak you must drain the system, repair the leak(s) and then put the system in a vacuum (1 ) to remove all the non condensable gases and (2) to make certain the sytem is tight. You can get as techical as you like but if the system holds a vacuum for a periosd of time it's tight and ready to refill.
This doesn't matter if you are using Freon or Freeze 12. If your system is low the gas went somewhere and until you find the leak and fix it you really haven't fixed the problem.

Agree with your opinion of Gordon. We went to his school last year in Tennesee.

Agree with everything except the leak part: It is incorrect to say that a system does not leak. All equipment has leakage to some degree. A system that operated for ten years or more is called a tight system, the system still has leaks but not enough to show on a gauge or affect cooling performance. No pressurized equipment is perfect. If you ever looked at a solder joint under a microscope you would wonder how it ever holds anything. Also in automotive, seals have a tendency to dry out more in winter months causing gas to escape just from not using the system. This is why some vehicles hold a charge all summer long....then next summer, the gas is gone.

 

[motorman]

Agree with everything except the leak part: It is incorrect to say that a system does not leak. All equipment has leakage to some degree. A system that operated for ten years or more is called a tight system, the system still has leaks but not enough to show on a gauge or affect cooling performance. No pressurized equipment is perfect. If you ever looked at a solder joint under a microscope you would wonder how it ever holds anything. Also in automotive, seals have a tendency to dry out more in winter months causing gas to escape just from not using the system. This is why some vehicles hold a charge all summer long....then next summer, the gas is gone.

that is why you should run your A/C 12 months a year. my 88 silverado still runs the same R-12 it came with but i do use the A/C all year long.

 

[Kid_Again]

500 microns IS 'way down there. I hate to sound like a Bubba but when I re-installed my VA kit (134Ra), I just used the air driven vacuum pump from Harbor Frieght (works off the venturi principle) and then pumped it up with Envirosafe. Two years, no problems but perhaps a newer system is more forgiving.


BTW, what are the signals for me to replace a drier?

Thanks

 

[rrubel]

Guys, I *did* replace all the seals. That's why I had my mechanic drain the system - so any residual Freon wouldn't get vented to atmosphere. Then I refilled it with Freeze-12. Hopefully I did the seals right (the sizes were somewhat different on what I took off, but they didn't look original so who knows what was there).

Oh, and he did pull a complete vacuum...

[RICHR]

 

[G Winter]

I use an old refrigerator compressor for a vacuum pump. Works just fine though, and the price was right. Open up the high side of the pump. add a line tap to the low side and block the end. Thats all it takes you got a cheap vacuum pump.
Glenn

 

[geekinavette]

You can get as techical as you like but if the system holds a vacuum for a periosd of time it's tight and ready to refill.

While that's a good indication it is by no means a guarantee that the system will hold pressure...big difference between 20-something inches of mercury and 300+ psi of pressure.

If using Envirosafe it is not necessary to pull a vacuum...in fact it is recommended that you do not pull a vacuum. I didn't pull a vacuum at all and it works quite well...vent temps stay mostly at about 38 deg F (except sitting idle in traffic).

Bill

 

[tyrel]

While that's a good indication it is by no means a guarantee that the system will hold pressure...big difference between 20-something inches of mercury and 300+ psi of pressure.

If using Envirosafe it is not necessary to pull a vacuum...in fact it is recommended that you do not pull a vacuum. I didn't pull a vacuum at all and it works quite well...vent temps stay mostly at about 38 deg F (except sitting idle in traffic).

Bill

This is standard procedure when refilling an a/c system, you pull a vacuum to -29 hg and let it sit for an hour or two, if the vacuum doesn't hold you check for leaks, tighten up, and pull it down again. Some people pull a vacuum two or three times to boil off all the impurities. This is how a/c is serviced and has been done this way for decades. I'm glad your a/c works and you get 38° at the vent, but I've never heard of not pulling a vacuum prior to recharging, it just isn't done that way.

http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7931

 

[geekinavette]

Oh I'm not saying that pulling a vacuum isn't a good idea to check for leaks...if there's a "big" one that'll certainly show it. In fact I did indeed do just that...and even though it held 25" just fine for two days, it wouldn't hold more than 60psi of pressure when charging...had a leak at the condenser.

I didn't pull a vacuum when charging it because the Envirosafe instructions say not to! If I lived in a very humid climate I would probably ignore that and do it anyway...but it is very dry here. The main reason for pulling a vacuum as I understand it (and I am by means no chemistry expert) is because the flourocarbons (sp?) do not get along well at all with moisture (R12, R134)...but the hydrocarbons don't care (Envirosafe).

Bill

 

[nyernga]

Huh. Len, I didn't ask about what else he did other than draining the R-12. I'll ask tomorrow. Hate to sound like a moron, but what did you mean by getting below 500 microns? I thought a micron was a size measurement...
[RICHR]

Just recovering the freeon isn't enough. You need to pull a vacum down to 500 microns to remove moisture and make sure it holds at that point. I'm sure he did a vacum but there may still be non condensibles if he rushed it.

Len

 

[Robertwav1]

that is why you should run your A/C 12 months a year. my 88 silverado still runs the same R-12 it came with but i do use the A/C all year long.

Very true, however, it's sort of a double edged sword. Liquid migrates to colder parts of the AC system in the winter time. Some systems have temperature protection that don't allow the compressor to turn on below the 50° mark. The compressor is strickly a gas pump only not a liquid pump which would aid to it's early demise. I don't mean to rattle on about the tech stuff, I guess I've been hangin' round the refrigeration forums too long!