I’m back with a long overdue post in my Cold Comfort series detailing early automotive air conditioning systems. Today we’ll be looking at the factory system in this 1955 Cadillac Fleetwood I found at Hershey this past fall.
A quick refresher for those new to this series: Factory air conditioning was first introduced in 1939 by Packard, quickly followed by Cadillac in 1941 and Chrysler in 1942 (full story here). Factory A/C then disappeared after World War II, not to reappear until 1953 when it was independently reintroduced by GM, Chrysler, and Lincoln.
This first-generation trunk-mounted system was used by Cadillac from 1953 through 1956 (Cadillac switched over to an underhood cowl-mounted system in 1957). This system was also used by Buick and Oldsmobile starting in 1953, but you are far more likely to see it in a Cadillac, like the featured car. Not surprising, given the $620 cost (about $6,000 today) of the factory A/C option.
Like many early factory setups, it could be installed directly at the factory, or by the dealership as an add-on. These early 1950s Cadillac systems were superficially similar to their pre-war predecessors: Aside from the obvious similarity of being trunk-mounted, they also operated independently of the heating system. However, there were some key differences: For starters, these were now true factory systems, unlike the pre-war systems which required post-assembly shipment to an outside vendor for A/C installation.
Indeed, GM was actually working on two completely different air conditioning systems at this time: The Frigidaire system featured in this article, and the cowl-mounted Harrison system that I covered in a previous post.
Another difference from the pre-war systems: Cadillac (and the other OEMs) added exterior fresh air intakes to allow fresh air to be blended with recirculated inside air, like the one pictured above. I’m sure this improvement was much appreciated by all the smokers (and non-smokers) of the era. Unfortunately, if you wanted to adjust the amount of fresh/recirculated air blend, you had to do so by means of a knob on the rear parcel shelf: The setting could not be adjusted by the driver.
Furthermore, Cadillac added one other innovation that was quickly copied: Instead of just pouring the cold air straight out through an opening in rear parcel shelf (fogging the rear windows and freezing the necks of the rear passengers), Cadillac placed diffusers in the ceiling of the passenger compartment, and connected them to the trunk-mounted evaporator using large tubes (made of clear plastic to reduce the impairment of rearward visibility). This allowed for much better air distribution throughout the entire passenger compartment.
While I still have yet to see a 1953 or 1954 Cadillac A/C system in person, the featured 1955 system is very similar in overall configuration. That said, there were running changes made along the way. 1954 introduced an electromagnetic clutch and a power switch. The compressor on 1953 Cadillac A/C systems ran continuously with the engine and required removal of the belt to disengage the system.
For 1955, Cadillac updated the control panel, pictured above. For 1953 and 1954, you just had just two blower knobs: The only way to control the temperature of the car was by adjusting the fan speed, while the compressor constantly ran.
For 1955, the control panel still has the two blower controls, but also added a slider control for temperature. This temperature lever did not control a blend door to the heater core like on modern systems: Remember that the heat and A/C were still totally separate systems at this point. Rather, the temperature lever controlled the output from a thermostat mounted in the air return in front of the evaporator, which then cycled the compressor on and off based on the temperature setting and the temperature of the air returning into the evaporator.
Cadillac used these cool ceiling mounted diffusers through the entire 1953-56 run. They are fascinating pieces from a different era of manufacturing. There is a ball-and-socket jet that can be used for directional cooling (similar to what you might find on an airliner). There are also two flaps that can be opened for a more diffuse flow of air. “Regular” Cadillacs had four of these outlets, but the Series 75 limousine had six.
One final fun fact: Cadillac made Air Conditioning available on their convertible models starting in 1956. To my knowledge, this was the only convertible ever offered with a factory trunk mounted A/C system. Unlike the closed cars, the A/C convertibles did not have an external fresh air intake: Instead, they recirculated inside air via two central air returns located behind the well for the top (the air return for fixed roof cars ran under the rear seat). Obviously, there were no ceiling-mounted diffusers, so with only rear vents, this system would have only been effective with the top raised. As a result, Cadillac produced less than 50 convertibles with A/C in 1956.