After having covered most of the early GM and FoMoCo factory A/C systems, I’ll be turning my attention next to Chrysler, who made some truly interesting systems over the years. For today’s installment, I’ll cover Chrysler’s first postwar system, the Airtemp system first seen in the 1953 Chrysler and DeSoto models.
1953 was a banner year for automotive air conditioning. After making a brief appearance in 1939, A/C went on a long hiatus until 1953. In this year, Cadillac, Buick, Oldsmobile, and Lincoln would all launch factory A/C systems, along with Chrysler and DeSoto (remember that Imperial wouldn’t become a separate brand until 1955). I’ve previously covered the Cadillac and Lincoln systems, so today it is Chrysler’s turn in the cold seat.
By 1953, Chrysler Airtemp was already a well-established brand in the commercial and residential cooling space, having entered the market back in the 1930s. So it seemed natural to bring this expertise and brand name to their automotive effort.
Like the 1953 Lincoln and GM systems, the Chrysler Airtemp system utilized a trunk-mounted evaporator with fresh outside air inlets on the rear fender. The inlet grilles on the Chrysler look tidier than the chunky scoops that Ford and Lincoln employed to draw in fresh air.
Like these other early trunk-mounted setups, the evaporator both discharged cooled air and recirculated inside air through the rear parcel shelf. Unlike GM and Lincoln, Chrysler did not use ceiling-mounted diffusers with clear plastic ducts to distribute the air, and instead discharged the air right into the parcel shelf. To avoid freezing the rear passengers’ necks, cold air was discharged through the center register, while the outboard ones were used for air return (opposite from Lincoln and GM systems).
Unlike the GM and Ford systems, the Airtemp used two condensers, as shown above. The first one was in front of the radiator as on modern systems. The second condenser was located behind the front bumper. The one in front of the radiator was rather spindly, likely to minimize the impact on the existing cooling system.
The Chrysler system was also unique among early systems for using R-22 as a refrigerant (as opposed to R-12 which everyone else was using at the time). R-22 operates at higher pressures than R-12, and is therefore almost exclusively used in residential and commercial systems: Indeed, this is the only automotive application of R-22 I’ve ever seen.
The engineers who worked on the automotive Airtemp system must have selected R-22 because it was familiar to them, based on their previous work on household and commercial Airtemp systems. Note the use of flared fittings in the pictures above and below: R-22 can be corrosive under certain conditions, and also operates at higher pressures than R-12, which dictated the use of flared fittings over traditional O-ring fittings.
As a result of using R-22, the compressor on the Airtemp is massive: a V4 unit requiring two belts and displacing a healthy 10 cubic inches (164 cc). This thing must have really eaten into gas mileage and performance when it was running, which would have been all the time since there was no electromagnetic clutch. As with all early A/C systems, removing the belts was the only way to turn the system off. As a result, contemporaneous accounts indicated that Chrysler’s was the most effective of all the 1953 A/C systems, a claim that I will likely be unable to independently verify in my lifetime.
The system was controlled by a single three-position blower switch to the left of the steering wheel (the off position only turned off the blower, and not the compressor). The temperature setting was preset at the factory and required a trip to the dealer to adjust(!).
Adjusting the blend of fresh and recirculated air requires stopping the car, opening the trunk, and flipping a damper.
Enjoying this continuing series on automotive A/C systems.
All logical, informative and entertaining with lots of clear pictures.
As a life long resident of often hot and always humid New Orleans; I have been fascinated by auto A/C since grade school.
Keep the entries coming, Tom Halter!
+1
Who says the digital car is a current phenomenon. The last picture shows the digital effort required to change the fresh/recirculated air.
Great article. Fascinating. How much did this system add to the sticker? Any idea how many were actually sold?
Between being hampered by the 2 speed automatic transmission and the huge A/C compressor engaged all the time; the pictured car must have been quite a bit slower than the stick shift, non A/C model?
Without a cycling compressor or air-blending ductwork, how did the dealer-only temperature adjustment operate? I am guessing that some adjustment of the evaporator inlet valve could be how, but perhaps the “control line” also did something other than return surplus refrigerant to the compressor?
Ask and ye shall receive! Here is a detail picture of the temperature control valve from the 1954 Dodge service manual (which essentially used the same system).
As you can see, there is an adjusting screw that basically adjusts the spring tension on a plunger in the expansion valve.
The item in Fig 10 is a thermal expansion valve.
I read some time back that Airtemp went back to then Walter Chrysler was seeing to the construction of the Chrysler Building in New York. I believe it opened in 1929 and was one of the first air conditioned buildings built – although it was only the ground floor or maybe the first 3 or 4 floors (I can’t recall now). It was a home-grown effort that, like marine engines, became a part of a very diversified business by the early 1930s.
It is kind of amazing to me that those early systems ran with a compressor engaged at all times. Even some kind of manual lever that allowed the belt to slack via a tensioner would have been an improvement, even if it required raising the hood once in awhile. But then I guess that anyone with enough mechanical ability to throw a lever under the hood would have been qualified to remove belts, too.
I recall those “matched set” belts being common on A/C compressors through much of the 70s. I spent some time working in wholesale auto parts and remember learning that two belts of the given part number had to be a specially-marked matched set to work on twin pulleys like shown here in order to guarantee the same stretch characteristics.
The early Lincoln A/C systems had bolts that allowed you to decouple the pulley from the shaft, essentially allowing the A/C pulley to “free wheel.” Still inconvenient, but at least you don’t have to remove a belt.
This is why so much effort was put into developing electromagnetic clutches, which started appearing as soon as 1954.
All of these early 50’s A/C systems were immature rush jobs intended to respond to the rapidly rising popularity of aftermarket A/C (which truth be told also suffered from most of the same limitations).
Following on with the “preset temperature” thread, this page from the 1954 Dodge service manual makes it abundantly clear that the driver was only expected to adjust the blower speed and nothing else. Even the fresh/recirculate blend door in the trunk was expected not to be used under most circumstances.
Great article and pictures of these fascinating systems.
I sure think, though, that rear-seat passengers would have might chilly heads with that cold air discharge on the rear shelf, even if it’s in the middle. I’d love to hear how effective these actually were from folks who experienced them when new.
When I think of Chrysler and Airtemp, I immediately think of Chrysler’s display at the 1939 World’s Fair, where Chrysler cars were displayed in an Airtemp air conditioned hall decorated with ice-covered “palm trees.” Chrysler called it the Frozen Forest.
Question when did automotive R12 start to be used? It is better than R134.
R12 has been used on automotive A/C since the very first systems appeared in 1939. Only in recent decades has the industry transitioned over to other refrigerants (R134a and more recently R-1234yf). Look for an upcoming post to demystify these refrigerants.
Great read Mr Halter, thank you!
As to concerns of no clutch, it actually isn’t that big of a deal in parasitic losses to keep spinning an unloaded pump. Yes, it’d be better not to, but not a deal breaker in those days. IE power steering.
Even after the advent of the electromagnetic clutch many systems “pumped” almost all of the time. Only the cycling clutch systems dropped In and out. The rest were pressure regulated and so except for a deliberate shut-off, the compressor was spinning away.
Ditto the similar situation in trucks with with air brake compressors – if the engine is running the compressor never stops turning. Even with no anticipated air demand for hours, it keeps churning away. There again, an unloaded pump is not a noticeable heavy drag.
As to flare vs O-ring fittings… either are adequate in AC’s range of operation. The decision to use flare was probably one of familiarity or availability, rather than R22’s vapor pressure.
How about Mr Howard Hughes’ similar “hermetically sealed” Chrysler?
Anybody ever heard the low down on that system? I sort of vaguely recall reading about the details long ago.
I saw the Hughes car on display at the Imperial Palace auto collection in Las Vegas about 15 years ago. There was an elaborate filtration system that took up the remainder of the room in the trunk. I don’t know any details about it, though.
I was in the refrigeration wholesale business for several decades.
“Pump” is the common, yet incorrect way used to describe a refrigeration compressor. It does not “pump” liquid refrigerant. Under normal operating conditions it “compresses” a low pressure vapor into a high pressure vapor.
The older style industry standard R-12 auto systems utilizing a Thermal Expansion Valve (TXV) employed a receiver between the condenser and TXV to 1) insure there was an adequate supply of liquid refrigerant when needed and 2) store excess liquid refrigerant when not needed.
The TXV controlled the amount of liquid refrigerant it used in order to maintain the correct superheat.
I’ve learned never to scroll past these innocuous looking articles — they are terrific! Most of these technologies predate me, but it puts one in a better position to appreciate something that was a major automotive development that’s routinely both overlooked and appreciated today!
I forget where I read it, but the Kelvinator system built for John Hamman, Jr., used R-22, which would have made sense at the time.
I used to have an extensive collection of Chrysler service and engineering literature, and I recall reading that R22 was chosen because it allowed a lower rotative speed for the compressor versus other refrigerants—one reason why I remember it is it set me checking after that word “rotative”; I learnt it’s a perfectly cromulent word. Whether low compressor rotative speed was actually a deciding factor (perhaps because it would be running all the time?) or a rationalisation after the fact, it seems borne out by the giant diameter of the compressor drive pulley—looks to be about 8 or 8-1/2 inches.
Interesting that this early compressor has four cylinders and displaces 10 cubic inches; I would’ve expected more if only because the later 2-cylinder Chrysler compressors displaced 9.45 cubic inches (V2) and 10.5 cubic inches (RV2).
I’m not sure whether or not I’m seeing any fins on the condenser pipes, though I would think there must be. If they’re there, they remind me of the condenser design on a 1949 Frigidaire refrigerator my grandparents had.
R-22 may have been initially chosen for that reason, plus the fact it has more “bang per buck” than R-12. As we all know, R-12 was the winner in the automotive world.
For many reasons.
I have come across a handful of 1954 Dodges with factory Airtemp as well as two late in the year 1953 Dodges with factory Airtemp. Here is a picture of one 1954 that I could locate easily.
Thanks again, Tom – Always fascinating to read your tech pieces. This is obviously some serious third-level nerdiness, but surely isn’t that why we’re all here anyway? Keep ’em coming, sir! 👍👍🙌🙌
I think that’s George Fenneman doing the voice over on this. DeSoto was a sponsor of “You Bet Your Life” with Graucho Marx and Fenneman at this time. Remember watching many episodes of this program when I was very young.
Choosing R22 may have been done to help with idle cooling , while the head pressure is higher, R22 can still achieve a cold evaporator temperature even as your condenser temp rises.. esp with lower compressor RPMs. R12 likes to boil even under pressure at a somewhat low temp thus if you boil off refrigerant in the high side you lose capacity quite quickly .
Large pulleys on the compressor allowed for the driver to still have full range of engine RPM without worry of damaging the compressor (since you couldn’t turn it off). Using a refrigerant capable of still maintaining good cooling at idle was a big factor..
R22 was used on bus air conditioners of the same vintage (and much later).. all of the GMC coaches used R22 and larger but similar compressors (6 cylinder 10-12 Ton).. the bus units used an air actuated manual transmission style clutch to turn on and off.
The greyhound Scenicruisrrs with lots of extra large windows all featured air conditioning.
Most will remember the GMC city busses “New look” or fishbowls of the 60s-80s, you could tell if one had AVC as it had a huge wart above the back window (condenser) and the evaporator was actually under the bus..
I’ve been fascinated with air conditioning since the 1970s and started experimenting with ways to increase performance as early my term years on dads IH scout and his GTO.. pretty much to this day if I own it then it’s going to have ice cold A/C.. from classic cars to classic busses I always delight in making the air conditioner work right
The facts are that R-12, not R-22, was was chosen as the industry standard for automotive A/C for many reasons. So many that I will not expand on the reasons here.
I would venture to say the higher critical temperature of R12 would be a big one.. its not hard at all to imagine reaching critical temperature under the hood of a car on a hot day and even in parts of the condenser esp where air recirculation occured.. the GMC busses I mention largely had the A/C isolated from the engine compartment.. the compressors were driven with driveshafts that allowed them to be located in a side compartment of the bus.. and the condensers were up top..
anything running at a higher pressure (think hot under-hood) is also more susceptible to leaks as well.. R-12 was a great fit for automotive and even home refrigeration.. im sure theres a ton more reasons why to use it vs something else.. ive done a lot of refrigerant experimentation with various things over the years and R-12 is hard to beat.. hydrocarbins are a different story. and something that seems touchy to many so I wont go into the numbers ive gotten with those.. the industry for fixed and portable A/C is starting to introduce them in more than just ice-plant production now but theres lots to learn still..
Anyone know if Chrysler offered A/C in wagons, pre-1955, as shown in the 2/2023 Hemmings? I just sold my ’54 NYer with factory A/C. It worked much better than similar GM units. Once the car was cooled down, MED setting was fine on a warm day. The whole cabin was well and evenly cooled. The unit sapped some power from the car and MPG, but was worth the comfort. The unit added $595 to the cost, plus $20 for the Solex glass.
Only a couple of years late in this observation, but better late than never.
While the Chrysler Airtemp condensing unit would run continuously (big pulley, so relatively slow rotation), the refrigerant was *not* circulated throughout the system when switched “off,” only when “on.” When “off,” the refrigerant was bypassed and was not recirculated, and the drag from the condensing unit (compressor) was thus reduced during “off” operation. Wear and tear on the compressor was relatively minor anyway, as the V-4 design turned slowly and was a precision unit designed for many years of trouble-free use. The need for a clutch came about due to parasitic drag on the engine, thus reducing fuel mileage.
Chrysler’s Airtemp AC unit was generally considered superior to any other system of the day, far more powerful than competing units and very reliable.