Positive Cab Ventilation
 

A while ago while in the junkyard, I noticed that more modern pickups have oval shaped air check valves in the back of the cab below the bedline. Apparently, they have some kind of a flapper door to let the incoming air from the ventilation system escape thru a grated cover.
Has anyone ever tried installing these on their classic truck? It seems it would go a long way to improve the air flow of the heater and kick panel vents and I surmise it would reduce the wind noise when cruising with the windows up and vents open.

Re: Positive Cab Ventilation
 

Yes about halfway down the page "Rear Cab Air Vents" - https://talk.classicparts.com/thread...p.13928/page-2

Re: Positive Cab Ventilation
 

Vents like that are the reason that vent windows disappeared.

Re: Positive Cab Ventilation
 

I remember the ads from Chevrolet when "Flow-Thru Ventilation" was introduced. The guy talking showed how cigarette smoke was cleared from the car by that flow.

Re: Positive Cab Ventilation
 

Did Chevy begin doing that on the squarebodies?

Re: Positive Cab Ventilation
 

I don't know about the trucks, but the cars got them in '71.

https://www.autoweek.com/car-life/cl...vrolet-impala/

Re: Positive Cab Ventilation
 

My mom had a Grand Am and saw something like what you describe near the frame of rear driver's side door.

On that car I figured it was to let the air push out when shutting door, with window rolled up.

Could this thing you describe be to displace air of a closing door?

Re: Positive Cab Ventilation
 

The squarebody vents out the bottoms of the doors.

Re: Positive Cab Ventilation
 

I used to follow LakeRoadster's build years ago and considered doing the same thing after removing my bed and redoing the wood. I think I ran out of time and never did look at it again. I still have the rear cab vents I removed from a couple of different model trucks.

Re: Positive Cab Ventilation
 

I have thought of doing something like that so that I could close my doors more easily. My doors shut great with the windows down but not as easily will them shut

Re: Positive Cab Ventilation
 

I also noticed when I shut my doors I notice that the roof shakes a lot. I wonder it that is because of the air not having anywhere to go.

Re: Positive Cab Ventilation
 

That could very well be if your cab is sealed up well.

Re: Positive Cab Ventilation
 

I've always been in the habit of opening the door, roll down window a few cranks, enter cab, close door. Depending on the season, roll all the way up, or down.

Re: Positive Cab Ventilation
 

What about when you leave?

Re: Positive Cab Ventilation
 

Same thing, only reversed. My kick panel vents being open probably aid in cab pressure relief.

Re: Positive Cab Ventilation
 

yah it probably doesn't help that I put speakers where my kick panel vents used to be.

Re: Positive Cab Ventilation
 

The guy that installed my weather stripping on recommended that I leave the section out that runs along the bottom of the door. I wonder if that will help. But then I wonder what problems will run into if I do. Especially wind noise. The only reason I am so concerned is because I keep on having problems with the bondo in the roof cracking.

Re: Positive Cab Ventilation
 

I did this years ago to get the doors to close like a modern vehicle. See this post in my build thread: https://67-72chevytrucks.com/vboard/...&postcount=645

Re: Positive Cab Ventilation
 

Good Idea. If only I didn't have my speakers located there.:lol:
I don't think it would work to put them in the door jams sense the gasket is on the inside of the jamb.

Re: Positive Cab Ventilation
 

If you place the vents in the rear door jamb, outside of the weatherstrip, it absolutely will work. Take a look at many vehicles from the '60's and '70's; that's a common location for the relief vent.

I didn't go that route, as that is where my speakers are hidden.

Re: Positive Cab Ventilation
 

Got it. I was thinking of it backwards. So that the air would be pushed inside the cab.

Re: Positive Cab Ventilation
 

I think I need to install something like this or else the bondo in my roof will continue cracking. I can see the roof shake every time I shut the door with the windows up