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R-12 Top-Off


EmTee
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I partially sidetracked the discussion in another thread with regard to the low refrigerant level in my '67 Riviera (https://forums.aaca.org/topic/376808-66-riv-trim-tag/#comment-2395162).  Well, inspired by that discussion I ordered an R-12 charge hose, which arrived today.  Since the temperature here today was 85*, I decided to attempt to add refrigerant to the system.

 

Now, I had already bought two 14-ounce cans of R-12 from the Turbinator a couple of years ago, but I have been reluctant to attempt this for fear of damaging the system, which still blows cold (well, cool) until the evaporator freezes up...

 

Anyway, with encouragement from @JZRIV and a quick review of the shop manual I felt confident enough to give it a shot.  As I said, the A/C was functional, but obviously low on refrigerant, as the sight glass was completely foggy (no picture).  Here's what I had to start:

 

image.png.74a7f9f7d43b424d84bb87c86c2176dc.png

 

I installed the charge valve and hose on the first can after cleaning the top of the can.  With the car on fast idle in the driveway I loosely attached the charge hose to the low-side schrader valve with the charge valve closed.  Then I further closed the valve to pierce the can.  Then I slowly opened the charge valve while watching the end attached to the low-side port.  Once I saw refrigerant leak from the connection I screwed the hose down tight and fully opened the charge valve.  The can immediately started getting cold.  I slowly rocked the can back-and-forth while watching the sight glass on the receiver-dryer.  It took several minutes to empty the can and here's what the the sight glass looked like just after beginning to fill from the second can:

 

image.png.e55e43bd6e6740a924da0587826261d9.png

 

Again, about ten or so minutes later, the second 14-ounce can was empty.  Now the sight glass is clear, as it should be when there's sufficient liquid refrigerant in the receiver:

 

image.png.bdbfd6c698892a3bad69875d4da9c5bc.png

 

I then disconnected everything and took a short drive to the gas station to top-off the gas tank.  Upon returning home I snapped this picture:

 

image.png.cf84645fbff39c43fdd38ba0eaed49cf.png

 

38* at the center A/C vent -- I call that success.  Hopefully there aren't any serious leaks and it will stay this way for awhile...  ;)

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Just shows A/C work is not the arcane voudou science some parties want you to believe it is.

 

I hope there's no significant leaks. If there are, if you can find parts, repair them. Lot of times it's as simple as a dried-out o-ring. Though it seems GM especially was fond of putting things like receiver-driers and evaporators in inaccessible places, requiring half the car to be disassembled to make the repair. Think 61-64 B&C bodies and 66-70 E.

 

The original guidelines indicated loss of approximately 1 lb of refrigerant per year was considered normal and adding a can was part of annual spring service. Then someone got bent out of shape over the ozone hole, which has been proven to expand and contract over millennia, when there was no R12 or other CFC to affect it.

 

Can you tell I don't trust agenda-driven "science"?👨‍🔬

 

Enjoy!

 

 

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6 hours ago, rocketraider said:

If there are, if you can find parts, repair them.

Parts are available; finding a shop willing to evacuate and reinstall R-12 is another matter.  Hopefully it'll hold for a few more years...

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I checked under the hood today and see what appears to be some fresh oil slung from the compressor shaft (area behind the clutch).  I'm guessing that's due to higher pressure now that the refrigerant level is where it should be.  I'm less optimistic about how long the charge will hold than I was yesterday, but we'll see...

 

I'm going to check the shop manual, but I seem to recall reading that the compressor shaft seal can be changed without evacuating the system.  Does anyone have any experience with that?

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NO, the system needs to be evacuated. When possible replace with the "Newer" type seal & mostly shaft seal leaks will be 'kinda" a thing of the past.

They DO make sealers for this type of leak but, the success rate is 50/50.

 

Tom T.

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Nothing should leak on a refrigeration system. Oil visibly coming out is a sure sign of a leak. "Topping up" is a backyard cure that eventually ends in disaster because nobody knows how much oil is still in the system. Non condensable gases (typically air) in a refrigeration system ruin performance. The air shouldn't get in as long as there is some refrigerant still in the system at all times. That is usually not the case with a leaky system, despite what the owner of the car probably thinks.

 

If you leave a system connected to a vacuum pump for 4 hours (or whatever the shop manual says) before recharging, the system will get cold. If you leave the pump connected overnight, the system will get colder.

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  In the mid '60's according to Buick it was acceptable for some refrigerant to leak past the front seal of the compressor. The justification was the slight refrigerant leak would carry some refrigerant oil with it to keep the front seal lubricated. This is documented in either the shop manuals or service bulletins...or maybe both, I don't remember which.

Tom Mooney

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I don't disagree that the system shouldn't leak if it is in good shape.  Obviously mine has issues.  Given that it is 55 years old and to my eye appears to never have been disturbed (at least no external component replacement) I'm not pretending that it has no issues.  Still, prior to the 'top-off' yesterday the system did try to cool the cabin.  Honestly, I did not expect the addition of refrigerant to restore the system to 'as-new'.  All I was hoping for was buying some time before having to perform a major system service (i.e., evacuate, leak test and repair).  There aren't too many days here (particularly this summer) where A/C is really necessary.  If I run the A/C a total of 2 hours per year that's a lot.  My main concern now is finding anyone competent and equipped for R-12 system service.  I would really rather fix any leaks and keep it R-12 rather than convert to R-134a.

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My concern with any R12 recovery machine is that it may have been compromised over the years with who knows what kind of refrigerant. I certainly wouldn't want my system refilled with its contents, unless I knew beyond doubt nothing other than R12 had ever been in it. And with all the chaos and confusion that was created when 134a was forced on us and people were grabbing at any R12 substitute they could get, that's a big gamble. You might get 12, but you might get flammables too. 

 

If you find a shop with a R/E machine, have them empty the system to keep the regulators happy, then repair any leaks and use your own virgin R12 to charge the system. It's still out there, and with the now-limited market it's not as prohibitively expensive as it was a decade or so ago.

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14 hours ago, EmTee said:

I checked under the hood today and see what appears to be some fresh oil slung from the compressor shaft (area behind the clutch).  I'm guessing that's due to higher pressure now that the refrigerant level is where it should be.  I'm less optimistic about how long the charge will hold than I was yesterday, but we'll see...

 

I'm going to check the shop manual, but I seem to recall reading that the compressor shaft seal can be changed without evacuating the system.  Does anyone have any experience with that?

I replaced a seal with compressor on the car many moons ago so it can be done but I remember it being a royal pain and swore I'd never do another. Need a special pulley puller. I believe I made one at the time. Like any rotating shaft seal, its efficiency is also related to wear on the steel shaft itself so sometimes replacing the seal with a slightly worn shaft may not achive the desired result.

 

I wouldn't disturb your syytem to replace the shaft seal as long as your system holds the charge for a decent amount of time and is working well which it sounds like it is. EVERY ONE one of these A6s I've had slung oil, even freshly rebuilt units I got done at Classic Auto Air. At some point, either aftermarket, factory, or both, they made metal shields that bolted to the compressor to keep the oil from slinging up on the underside of hood and other areas. These are still available in aftermarket I believe but they are easy enough to make. I made a custom one for the 66MZ car.   

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10 minutes ago, JZRIV said:

At some point, either aftermarket, factory, or both, they made metal shields that bolted to the compressor to keep the oil from slinging up on the underside of hood and other areas.

I do remember seeing some cars with those (later 70s?)!  The ones I saw would have been factory or dealer installed.  Thanks for the input; I'm going to monitor the A/C performance going forward while trying to ultimately identify someone equipped for servicing the system and properly addressing leaks.

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11 hours ago, EmTee said:

I don't disagree that the system shouldn't leak if it is in good shape.  Obviously mine has issues.  Given that it is 55 years old and to my eye appears to never have been disturbed (at least no external component replacement) I'm not pretending that it has no issues.  Still, prior to the 'top-off' yesterday the system did try to cool the cabin.  Honestly, I did not expect the addition of refrigerant to restore the system to 'as-new'.  All I was hoping for was buying some time before having to perform a major system service (i.e., evacuate, leak test and repair).  There aren't too many days here (particularly this summer) where A/C is really necessary.  If I run the A/C a total of 2 hours per year that's a lot.  My main concern now is finding anyone competent and equipped for R-12 system service.  I would really rather fix any leaks and keep it R-12 rather than convert to R-134a.

  Not using the system often enough presents problems for the compressor front seal. The period owners manuals often note this and encourage owners to operate the system occasionally during the winter months.

Tom Mooney

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6 minutes ago, 1965rivgs said:

Not using the system often enough presents problems for the compressor front seal.

 

Well OK then -- that I can certainly do!  ;)

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1 hour ago, 1965rivgs said:

The period owners manuals often note this and encourage owners to operate the system occasionally during the winter months.

Factory solved that problem in early 70s by changing the control wiring so the compressor ran in DEFROST/DE-ICE, which would be used in cold weather when A/C wasn't. Though I think the change was more to blow dehumidified air thru the defroster to reduce fogging on cold rainy days.

 

Olds went around its arse to get to its elbow to accomplish the same thing 1968-70. They used a compressor hold-in relay. Once you selected an A/C position, the compressor engaged and would not disengage until the car was shut off, no matter which position was selected. Handy for defogging if you knew how the system worked, but murder on gas mileage! Not sure if the other Divisions used it.

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  • 2 weeks later...

It was 95* F here today, so I took the Riviera for a ride with the windows up and A/C on.  Blowing 35* F out of the center vent on RECIRC.  Sightglass is clear, but still slinging some oil from the front seal...

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I have a contact in Fayetteville, NC who has two cans of R12 he wants to sell. I don't know how much he wants for them.

 

Send me a private message if you are interested and I will send you his name and phone number.

Edited by NC1968Riviera (see edit history)
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On 7/23/2022 at 9:36 PM, EmTee said:

It was 95* F here today, so I took the Riviera for a ride with the windows up and A/C on.  Blowing 35* F out of the center vent on RECIRC.  Sightglass is clear, but still slinging some oil from the front seal...

Now imagine yourself doing same thing back in 1967 when A/C in cars was still relatively uncommon. You'd feel like a you were a king! And 55 years later......no different.:-X22

Just get one of these. can probably find it cheaper or make one. https://www.corvettecentral.com/c3-68-82/heater-air-conditioning/air-conditioning-compressor/63-76-air-conditioning-compressor-pulley-shield-452133

Edited by JZRIV (see edit history)
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5 hours ago, JZRIV said:

Now imagine yourself doing same thing back in 1967 when A/C in cars was still relatively uncommon.

And in houses too. Was working at local historical society last week and someone mentioned the first window unit airconditioner in their neighborhood, installed in... summer 1967! The fellow said everyone in the neighborhood came to see it.

 

We had a family reunion near Pinehurst NC in August 1967. Some of my dad's cousins had moved to upstate NY after WW2, and was not unusual for them to wear jackets in July.

 

They had a new 1967 Caprice sedan, dark turquoise with matching interior and black vinyl top. Gorgeous and nicely equipped car- but no airconditioning! 

 

They drove it to NC for the reunion. August in the NC Sandhills is HOT. 2nd day they were there that car went to Sears to have an airconditioner installed!

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There is more to converting to R134a than just taking out all the R12 and oil, changing the fittings and recharging with R134a and its compatible oil. The pressures required are different between the two refrigerants. That is solved by putting in a R134a spec'd POA valve. Most people know enough to do that. But most of the "converted to R134a" cars I see online do not do a critical thing. You need to change the condenser from the original condenser with 3/8" tubing with a high efficiency condenser with much smaller and more numerous tubes. The cooling fins tend to be smaller and more numerous too on the newer ones.  I have bought a few cars from the 60s and 70s that were "converted" and they performed rather poorly UNTIL I changed out the condenser. 

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I will reinstall all the air conditioning system in my 67 (removed by one of the previous owners) and we can't find R12 in France anymore.

They've put on the market the Duracool 12A, which replaces R12 and R134a, so i'll probably test it. 

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On 7/28/2022 at 6:37 PM, Kink56 said:

There is more to converting to R134a than just taking out all the R12 and oil, changing the fittings and recharging with R134a and its compatible oil. The pressures required are different between the two refrigerants. That is solved by putting in a R134a spec'd POA valve. Most people know enough to do that. But most of the "converted to R134a" cars I see online do not do a critical thing. You need to change the condenser from the original condenser with 3/8" tubing with a high efficiency condenser with much smaller and more numerous tubes. The cooling fins tend to be smaller and more numerous too on the newer ones.  I have bought a few cars from the 60s and 70s that were "converted" and they performed rather poorly UNTIL I changed out the condenser. 

 

Curious as to whether you have any suggestions as to sources for the POA valve and condenser to work with R134?  Would the STV valve remain in the system?  

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First, contrats on a quick and relatively cheap fix with success. However, sometimes I've not been so lucky. 

 

R-12 is about $20 per pound give or take. Investing in some inexpensive gauges and a vacuum pump ($60) is a prudent measure for others in a similar situation.  By evacuating the system before adding refrigerant and confirming no leaks, If there was a leak without testing first, you would not have wasted a pound or more of R-12. Ask me how I know? 

 

https://www.amazon.com/Orion-Motor-Tech-Conditioning-Maintenance/dp/B08V5JWJSB/ref=sr_1_3_sspa?gclid=EAIaIQobChMIvITMrIW0-QIV1Bt9Ch0wEQGzEAAYASAAEgLzx_D_BwE&hvadid=410037927523&hvdev=c&hvlocphy=9052460&hvnetw=g&hvqmt=e&hvrand=7058989007119826229&hvtargid=kwd-316671003563&hydadcr=7466_11110444&keywords=r12+gauge+set&qid=1659851679&sr=8-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExU1pOWTRZSVdVTk5HJmVuY3J5cHRlZElkPUEwODExNTM0MVpEUDVWVDJKTjczNSZlbmNyeXB0ZWRBZElkPUEwNDQ0MzE1MlJDREc0SzkwNTVHMCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

 

https://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

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