BangShift.com Comfort And Safety: A Closer Look At GM’s 1971 Forced Air Ventilation System

(Words by Scott Liggett) As the ’60’s were ending major changes were happening in the auto industry. Safety became a serious concern in vehicles. In 1966, there were Congressional hearings where people like Ralph Nader, author of “Unsafe At Any Speed” and Byron Bloch were pushing national safety standards on all vehicles. By 1968, all vehicles were required to have things like collapsing steering columns, four way flashers, side marker lights, three point seat belts for front seat occupants.

Air flow through the cabin of the car was also on the minds of automakers. Presumably, trying to prevent carbon monoxide poisoning. In 1969, GM coined the term Astro Ventilation. This was a system where fresh air was constantly moving through the car whether the windows were open, or the AC or heat were on, or not. The air flowed through the cowl vents at the base of the windshield, through the interior by vents in the dash, and out under the rear seat into the trunk.

In 1971, GM took this ventilation a step further. By positively moving air through the car’s cabin whether the car was moving, or not. This process is explained in commercials of the 1971 Impalas linked below. As long as the key was in the on position, a fan was moving air. Drawing air into from the cowl, through the HVAC system, the air was pushed out through the vents in the trunk lid.

I became aware of Flow Through ventilation in 1985 when I bought my first car, a 1971 Impala four door sedan. That is when I discovered the factory louvers in the trunk of the car. I thought they were really cool feature. Very similar to the louvers car customizers punched in hoods, trunk lids and such going back to the ’50’s. Since then I learned that GM used these vents on all their full size cars and their small Vega variants. But, for some reason they never put them on Chevelles, Novas or Camaros. By 1972, they were gone. Historians say that GM took complaints that the vents in the trunk lid caused leaks into the trunk of the car. My ’71 never had this problem.

Scott Liggett