The driver’s side still has (well, hopefully had…) some leaks. I never figured out for sure where it was leaking, but I’m sure the cowl opening was part of it like on the passenger’s side. I put one of the plastic cowl hats in place on the passenger’s side when I pulled the heater box, but never did the driver’s side. Since I had the interior out for the floor paint, I went ahead and took care of the cowl vent then.
I pulled the fresh air vent out (disconnect the control cable, remove 3 nuts—much easier than I was expecting) and there was a bunch of loose rust and other things up by the cowl. As on the passenger’s side, there was some surface rust, but the cowl seems to be in moderately decent shape overall. I cleaned up the rust the best I could with just sanding and a wire wheel on a mini rotary tool, then primed and painted the area.
Before putting the plastic hat, I also did some quick clean-up work on the fresh air vent itself and gave it a respray to make it look a little nicer. Once that dried, I put the silicone sealer around the bottom lip of the cowl opening. Then I “glued” the plastic hat in place with the sealer and held it in place by reinstalling the fresh air vent. Pretty simple overall.