Is this a cooling vent…

[UnsungZero_OldTimeAdMan]

GM? whats that?

Government Motors isn't it.

The "old" one. Wink. Wink.

Sponsored

 

[citizen]

It's there to vent and relieve air pressure... and create a curtain of air to smooth and reduce air turbulence (drag). The reason why aftermarket mud flaps and rally flaps are counterproductive.

Thanks for sharing, that was fascinating!