The only thing that makes me angrier than rust is actively seeking out & finding places where rust is begging to start. I took my bumper off and after digging all of the powder-coat-ruining rocks out of my powder coated tips, I took out the (once-flapped now flapless) quarter pressure vent to look inside. Found a horrific collection of rocks and crap just begging for rust to start. This post is for those of us who care about such things. Ridiculous design.

I cleaned out the panel, paint sealed it & made a new functional flap out of some duct tape. The actual part number is 62930-12160.
Oh and aside, it eliminated the rotten egg smell in the cabin as well - imagine that. Eliminated it. I could produce this smell on demand as I haven't been driving the car very hard the last few months. It's gone.

 

Same thing here. I gutted my trunk and that’s when I saw it. Thing is the oem piece the flap is extremely delicate and thin so with heat/cold and age it will break fully exposing your trunk to all kinds of trash.

 

What is the purpose of the vent?

 

I believe it is to relieve pressure when closing the door..