When I went through the GM Training Center in Dedham Ma in 1970, I am quite certain that we covered Astro Ventilation during the course of study. Basically Astro Ventilation was a marketing term used for a system that is still in use today. The air in cars needs to move to maintain a fresh air supply for the occupants. To accomplish this, early cars used vents that were manually operated, and the air usually entered directly through openings in the kick panals. As cars became more sophisticated, those "holes" that let in hot air in the summer, and freezing air in the winter were scrapped in favor of a much more civil system of exchanging air inside a vehicle. GM called their system Astro Ventilation, it was nothing more than an air inlet, usually at the base of the windshield that let in outside air. The "exhaust" outlets were in the rear of the vehicle, usually hidden behind a panal, or inside the trunk area, there was normally a rubber flap that acted as a "one-way" valve so the air flow was supposed to be continuous from front to rear. The air was introduced into the passenger compartment through the air ductwork as part of the HVAC system, and / or through normal gaps on the interior trim such as around the door handles. Hence the full term Heating, Ventilation, Air Conditioning. That's the quick down and dirty of Astro Ventilation as I remember it.
One note here, Studebaker was one of the first vehicles to incorporate this type of civilized system in their vehicles as early as 1965, maybe before. My Dad had a 65 Stude and that system was one of the major selling points that the salesman was quick to point out during his sales presentation. The rear exit vents were grills above the tailamp housings, on the inside was the rubber flap that I mentioned above, this rubber flap could be heard when shutting one or more of the doors when the windows were fully closed, you could hear the flap slap closed after the air had escaped. If one was standing at the rear of the vehicle when somebody closed a door, you could feel the air rush out of the vent grills.
On the C4s, you can see part of this system on the door jam of the body, it is a black plastic grill, inside you will find that infamous rubber flap.
I'll have to look over my C5, I haven't noticed where they are hiding it on these.
Incedently, this system actually moves some air even when the car is standing still, although greatly reduced. On a sunny day, the sunlight causes a "greenhouse" effect inside a closed vehicle, the air expands and is forced out those infamous rubber flaps and vented to the atmosphere. As the air inside cools slightly, more fresh air is drawn in through the inlets on the forward part of the vehicle, it can't get in from the rear vents because of those darn rubber flaps that allow air to travel in one direction only.
This is one of the many reasons that one doesn't see rear backlight windows blowing out on a hot summer day anymore, the air isn't trapped inside but is allowed to vent out.
Too bad this isn't an option for many people... LOL
I hope this information helps more than it confuses.
vettepilot
