Factory A/C in 1967-1972 Darts

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If you take the pusbutton switch out you can spray it full of silicone and push the buttons till it frees up. just be really careful with the vacuum lines.

If the switch is not mounted firmly and straight, you will get some side movement in the buttons which can make them hard to push. Mine had both problems.
 
If you take the pusbutton switch out you can spray it full of silicone and push the buttons till it frees up. just be really careful with the vacuum lines.

If the switch is not mounted firmly and straight, you will get some side movement in the buttons which can make them hard to push. Mine had both problems.

Be very careful with that plastic. It will likely be brittle and you can snap off the vacuum hose nipples by sneezing on them. What happens often is the back of the switch is held on with melted plastic pins. The pins get brittle and you push on the button and the back of the switch comes off because the pins broke. If you take it out I would put a dab of JB Weld on each side at that joint to take some of the load when pressing the buttons. I have seen some silicones attach plastic and make it brittle.... that was 1990's plastic. Will it bother 1960's plastic, I doubt it but be aware of it.
 
Filled to pressures for 134a in my local temp of 95-ish per several charts I found including one here on FxBO.

Vent tube through firewall is not plugged.

It's condensation on the outside of the box.

Thoroughly checked several times to verify.

Outside the box sweats? That is interesting. If it has not been out and apart I think I would pull it out and see what it looks like inside... maybe full of leafs or something and blocked airflow.
 
I've rebuilt a couple of the slider switches by melting off those pins on the back (or filing them so they allow the rear cover with the nipples to come off. I agree about being extremely careful with those nipples. Then separating the "wafers", being sure to keep them in the proper order, and oriented correctly. I believe I used locksmith graphite to lubricate them, then put them back together and either re-melted the pins or tapped, threaded and machine screws.

They came out great and easy to operate.
 
My car was garage kept by the first owner and carport kept by the second.
I had my hands down the vent stack as far as it could go before painting and there was minimal debris.

The evaporator case did leak when I got it but it was because the gasket was folded, causing it to have a gap. I fixed that and applied a very thin amount of clear silicone sealer at reassembly.
I also filed the gasket where the drain to the firewall goes from the inner box to the outer because I noticed it was particularly high there, causing the condensate to reach a high level on that side before it could overcome the gasket and exit via the drain.

I noticed no debris while I had the box open.

You can clearly see small droplets form on the outside of the evap box after about 20 minutes of operating.
It never freezes up, but the droplets move on any turn, and combine to form drops which then land on the floor.
 
I've rebuilt a couple of the slider switches by melting off those pins on the back (or filing them so they allow the rear cover with the nipples to come off. I agree about being extremely careful with those nipples. Then separating the "wafers", being sure to keep them in the proper order, and oriented correctly. I believe I used locksmith graphite to lubricate them, then put them back together and either re-melted the pins or tapped, threaded and machine screws.

They came out great and easy to operate.

I have done that successfully a couple of time too. Here in Az if the car was sitting out in the desert chances are that plastic is so brittle it will shatter with just the tapping operation. Now that I understand that physically all these switches are the same it is possible to buy the cheaper C body switches and a bit of rewiring you can make them work perfectly. The '66 Valiant was a '65/'66 only switch that NOS was over $400... nope. NOS C Body switch for $90, open it up like you said and bit of rework on the contacts and it works just fine.
 
Which condenser would you recommend?

Go here and pick out a true parallel-flow ("PF") condenser sized appropriately for the cutout in your radiator core support panel. Bigger is always better with a condenser; too big is not a thing.


I wonder if a more efficient condenser might help.

Probably. Take a look at this exhaustive set of tests: R12 and R134a (and a few others not worth thinking about), with tube-and-fin (old type) and parallel-flow (new type) condensers, at a variety of in-car ambient temperatures. Take a look at the differences in vent temps and high side pressures with the old versus new type condenser, especially as demand rises (higher in-car ambient temp).
 

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I have done that successfully a couple of time too. Here in Az if the car was sitting out in the desert chances are that plastic is so brittle it will shatter with just the tapping operation. Now that I understand that physically all these switches are the same it is possible to buy the cheaper C body switches and a bit of rewiring you can make them work perfectly. The '66 Valiant was a '65/'66 only switch that NOS was over $400... nope. NOS C Body switch for $90, open it up like you said and bit of rework on the contacts and it works just fine.

I've noticed that 66/67 B body appears to be the same as at least 71/71 A body.
 
Go here and pick out a true parallel-flow ("PF") condenser sized appropriately for the cutout in your radiator core support panel. Bigger is always better with a condenser; too big is not a thing.




Probably. Take a look at this exhaustive set of tests: R12 and R134a (and a few others not worth thinking about), with tube-and-fin (old type) and parallel-flow (new type) condensers, at a variety of in-car ambient temperatures. Take a look at the differences in vent temps and high side pressures with the old versus new type condenser, especially as demand rises (higher in-car ambient temp).

Wow... in all my time of working on the AC systems in Az temps I have never seen high side pressures like those with the factory system. My Coronet system will blow ice cold and I have never seen it over 220 PSI in all the testing I have done with it on the hottest days. I would warn this is a test that does not tell you how they maintained those input parameters and what the test setup was. It was also done by an auto AC sales company during the time when there was lot of R12 to R134 conversions going on... they wanted a reason to change out the condensers.... Just my 2 cents.
 
When I was a kid, I used to summarily dismiss data of any quality if it didn't agree with my opinions and preconceptions. ¯\_(ツ)_/¯
 
When I was a kid, I used to summarily dismiss data of any quality if it didn't agree with my opinions and preconceptions. ¯\_(ツ)_/¯

I am I retired engineer who has seen many times how data taken incorrectly or poorly can cause incorrect conclusions to be drawn. My job was to question data and analysis. Even in the field of trained engineers and scientists there is a lot of problems with poorly executed experiments. I don't trust any data unless I understand where it came from and how it was collected. That is all I am saying.
 
Wow... in all my time of working on the AC systems in Az temps I have never seen high side pressures like those with the factory system. My Coronet system will blow ice cold and I have never seen it over 220 PSI in all the testing I have done with it on the hottest days. I would warn this is a test that does not tell you how they maintained those input parameters and what the test setup was. It was also done by an auto AC sales company during the time when there was lot of R12 to R134 conversions going on... they wanted a reason to change out the condensers.... Just my 2 cents.

What year is your Coronet? I really like the 66-67’s and the 68-69’s. I like the 66 Polara and Monaco’s a lot too. The tail lights are really wild. I like the larger cars. There was a rust free 1966 Coronet 2 Dr hardtop with a slant six and auto in it about 5-6 years back for only $5,500 amazingly it took months to sell it.
 
What year is your Coronet? I really like the 66-67’s and the 68-69’s. I like the 66 Polara and Monaco’s a lot too. The tail lights are really wild. I like the larger cars. There was a rust free 1966 Coronet 2 Dr hardtop with a slant six and auto in it about 5-6 years back for only $5,500 amazingly it took months to sell it.

Only a few see the beauty of a /6 in a B-Body.

49206387_2076390442396862_5161547668899495936_n.jpeg
 
I am I retired engineer who has seen many times how data taken incorrectly or poorly can cause incorrect conclusions to be drawn. My job was to question data and analysis. Even in the field of trained engineers and scientists there is a lot of problems with poorly executed experiments. I don't trust any data unless I understand where it came from and how it was collected. That is all I am saying.
I agree. It is common practice in industry to tailor specifications for parts to the most favorable conditions. So they are not really lying, if you could maintain the ideal conditions, the part would perform as specified. However, your environment will likely not be ideal, so your performance will be less. I am an ‘almost‘ retired engineer as well.
 
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Only a few see the beauty of a /6 in a B-Body.

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Beautiful ‘68! I’d love to have one of those one day. How did you get snow in Arizona? I really like the round 68 only side markers on these Mopars too. I think you’re right about the 66. most people probably passed on the coronet I saw because of the slant six. But it didn’t bother me a bit. Although I would prefer the 318,I wanted it really bad and kept looking at the ad,but ended up buying something else and it eventually sold. Decades ago I saw a 1970 Challenger in a junkyard once with a slant six in it. I doubt too many were sold with slant sixes in them. Something that looked like that was expected to have some power to it.
 
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Beautiful ‘68! I’d love to have one of those one day. How did you get snow in Arizona? I really like the round 68 only side markers on these Mopars too. I think you’re right about the 66. most people probably passed on the coronet I saw because of the slant six. But it didn’t bother me a bit. Although I would prefer the 318,I wanted it really bad and kept looking at the ad,but ended up buying something else and it eventually sold. Decades ago I saw a 1970 Challenger in a junkyard once with a slant six in it. I doubt too many were sold with slant sixes in them. Something that looked like that was expected to have some power to it.

It is all about altitude. Phoenix is about 1000 feet... hot and little snow/rain. Tucson is about 2500 feet, more rain and snow ever 7-10 years. I am at 5200 feet so more rain and 2-5 snowfalls a year. Flagstaff 7000 feet, pine trees, rain and snow all winter.
 
I am I retired engineer who has seen many times how data taken incorrectly or poorly can cause incorrect conclusions

Sure enough. But you're also the dude who can't seem to get his Duster's A/C to work well, and who didn't know about the A-body systems not using an EPR valve til '74. I'm not saying that to rub yer nose in it, just to point out that there's always more for all of us to learn, even on the subjects we already know a lot about. Extensive knowledge on a subject can actually blind us to stuff someone with less experience might notice more easily, or question more readily.

Those high-side pressures that look alien to you don't imply that the tests were somehow rigged, just that the test system wasn't like the cars you're used to. That doesn't really matter; the important thing is that everything was kept constant except the two kinds of condenser. If they'd tested one kind of condenser in a '96 Toyota Corolla and the other kind of condenser in a '78 Chevrolet Caprice or something like that, that would've rendered the tests useless.
 
I've held the job title "engineer" several times although I' don't hold a "PE" degree.

One thing I've learned working with both types is that for some reason "engineers" are prone to a "can't see the forest for the trees" mentality for whatever reason.
 
The RV2 works well and is reliable, but quite a beast. Definitely don't buy factory AC parts for a non-AC car since it won't fit (firewall differs, post above). If you have a factory AC car, you could install a modern Sanden compressor to work with your existing climate box and evaporator, since lighter, smaller, and cheaper than a rebuilt RV2. See Bouchillon performance for brackets (or a post here for slant-six options). I would re-hose with modern "barrier hose". You can cut off the factory crimps to re-use the fittings. If no Mastercool crimper, can use Oeticker stepless ear-clamps, PEX clamps (some sized), or Breeze screw clamps. If changing to a more efficient parallel-flow condenser, I would use O-ring fittings except at required factory connections. With a Sanden, you won't need the metal suction bottle.

I use HC refrigerant (Duracool, Envirosafe, ...) in all my vehicles, even a 2002 Chrysler. It is compatible with factory mineral oil, but I use better PAO 68 oil (Duracool's Oil Chill). R-134A is being outlawed, R-12 is pricey ($100/can), and current R-1234yc needs different pressures (and pricey). Many claim/imagine that HC refrigerant "can explode", but they didn't take graduate course in combustion like me. No fire reported in the millions of cars which have been using HC for many decades, and it has been in refrigerators in Europe for decades. Carrying a newspaper in the cabin is a greater fire risk. All new products raise alarms from naysayers, like the silicone brake fluid and waterless coolant I also use. People once called chicken-little about electricity in the home (touch it and die), HEI ignitions, and one columnist even claimed electricity from a nuclear plant is radioactive. Science is tough for most who prefer belief.
 
The RV2 works well and is reliable, but quite a beast. Definitely don't buy factory AC parts for a non-AC car since it won't fit (firewall differs, post above). If you have a factory AC car, you could install a modern Sanden compressor to work with your existing climate box and evaporator, since lighter, smaller, and cheaper than a rebuilt RV2. See Bouchillon performance for brackets (or a post here for slant-six options). I would re-hose with modern "barrier hose". You can cut off the factory crimps to re-use the fittings. If no Mastercool crimper, can use Oeticker stepless ear-clamps, PEX clamps (some sized), or Breeze screw clamps. If changing to a more efficient parallel-flow condenser, I would use O-ring fittings except at required factory connections. With a Sanden, you won't need the metal suction bottle.

I use HC refrigerant (Duracool, Envirosafe, ...) in all my vehicles, even a 2002 Chrysler. It is compatible with factory mineral oil, but I use better PAO 68 oil (Duracool's Oil Chill). R-134A is being outlawed, R-12 is pricey ($100/can), and current R-1234yc needs different pressures (and pricey). Many claim/imagine that HC refrigerant "can explode", but they didn't take graduate course in combustion like me. No fire reported in the millions of cars which have been using HC for many decades, and it has been in refrigerators in Europe for decades. Carrying a newspaper in the cabin is a greater fire risk. All new products raise alarms from naysayers, like the silicone brake fluid and waterless coolant I also use. People once called chicken-little about electricity in the home (touch it and die), HEI ignitions, and one columnist even claimed electricity from a nuclear plant is radioactive. Science is tough for most who prefer belief.

I disagree on the factory ac swap. I did it on mine. It is not that bad. A tiny fraction of the work to restore a car. I had to drill a few extra holes in the firewall and cut out the blower motor hole larger. It is a lot of work, but can be done by anyone with good mechanical skills.
 
I disagree on the factory ac swap. I did it on mine. It is not that bad. A tiny fraction of the work to restore a car. I had to drill a few extra holes in the firewall and cut out the blower motor hole larger. It is a lot of work, but can be done by anyone with good mechanical skills.
You will have to drill 2 holes thru the firewall of a non-factory AC car for any type of AC compressor addition, unless you use the systems which replace the cabin climate box and route the hoses thru the big hole where your cabin fan used to sit. I suggested a Sanden because RV2 are getting harder to find, and that will only get worse, plus you would also need to source factory brackets to mount it to the engine. You may also need to change the crankshaft pulleys and others, as the belt routing varied over the years and between AC and non-AC cars. Buying a kit from Vintage Air and others is the easiest route, but expensive (>$1000). I spent ~$200 each for the AC systems I put in my three 1960's Mopars. Two had after-market systems from ~1970 with some parts I leveraged (knee-knocker boxes, York compressor w/ bracket).
 
You will have to drill 2 holes thru the firewall of a non-factory AC car for any type of AC compressor addition, unless you use the systems which replace the cabin climate box and route the hoses thru the big hole where your cabin fan used to sit. I suggested a Sanden because RV2 are getting harder to find, and that will only get worse, plus you would also need to source factory brackets to mount it to the engine. You may also need to change the crankshaft pulleys and others, as the belt routing varied over the years and between AC and non-AC cars. Buying a kit from Vintage Air and others is the easiest route, but expensive (>$1000). I spent ~$200 each for the AC systems I put in my three 1960's Mopars. Two had after-market systems from ~1970 with some parts I leveraged (knee-knocker boxes, York compressor w/ bracket).
I definitely agree with the sanden compressor. I wish I had used one instead of the original rv2. It would have made the belt routing so much simpler. I didnt get the pulleys and brackets with the factory ac I bought.

I also paid about $200 for the salvaged factory air I bought, so it was really cheap. The Vintage air units are closer to $2000 now all in. JPar did a really cheap knee knocker that worked out well. He has a good thread on it.
 
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