# Rear Wall Cabin Vents in Truck? SEAL OR NO??



## txdog27 (Sep 10, 2011)

Ok so i recently gutted my truck to line the entire inside of the truck doors, back, front, top and bottom, with sound deadener....which is a 2003 Dodge Ram Quad Cab by the way......and I noticed when I pulled off the foam piece that runs behind the rear bench seat that there are two square holes cut into the cab wall with black vent looking grilles with rubber luvers or flaps in them...

I am guessing these are some sort of pressure equalizers or air exchange vents and are probably there for a reason.....BUT.....what problems would come from sealing over them with dynamat?

Would they be minor annoying problems or really big problems like a/c not working or doors not closing....

Anyone with experience with this or advice on it?


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## thomasluke (Jun 10, 2011)

pics ?


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## underdog (Jul 5, 2011)

"what problems would come from sealing over them with dynamat?"

Doors that will not close unless you leave a window down.
Windows being blown out when you try to close said door after forgeting to leave a window down..
Poor performance of ventilation system?


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## jcollin76 (Oct 26, 2010)

I had a similar issue in my silverado. I put mat right up to them, then just covered them with a some ccf.
It'll still move air, just not as freely.

But they are also a huge issue with letting in road and exhaust noise. Something I wanted to try is... fab up a cover with some insulation or ccf, similar to an aperiodic membrane.

This would allow you to adjust between the noise rejecting properties, and still allowing air movement. It would need adjusting till you find a happy compromise.


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## south east customz (Jan 17, 2011)

underdog said:


> "what problems would come from sealing over them with dynamat?"
> 
> Doors that will not close unless you leave a window down.
> Windows being blown out when you try to close said door after forgeting to leave a window down..
> Poor performance of ventilation system?


It's not a good idea. Have done it before and didn't have the results of above but still had demonishing ac performance and "cabin pressure issues"


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## txdog27 (Sep 10, 2011)

So if I were to cut out some squares of closed cell foam or equivalent and out them over the vent openings and then ran the dynamat all around it would that be a good compromise?

I know I gotta do something about these things because it is a horrible source of road noise and wind sound while driving without the rear seat and that foam piece covering them......


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## txdog27 (Sep 10, 2011)

Also, do the vents really have to be that damn big? Lol ... these things on an 03' dodge ram are huge....about 7 1/2" x 7 1/2" square...are they this big on chevy, ford, toyota, etc? 
Maybe completely cover half of them and then put foam across the rest? Idk


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## jcollin76 (Oct 26, 2010)

I will say that when I tried covering mine, it did affect ac performance and pressure in the cabin.

Covering completely is not a good option, but figuring it out will take some experimenting. A sound buffer, but still allowing air exchange is a tough one...
I even tried luxury liner pro tacked to the back of my seat, to hopefully block some noise, but allow air to get behind it and to the vents. Works okay, but not the best.

I'd actually like to revisit it in my install, and see if I can get a better solution. So I'm right there with ya bud.

Lol the ones in the silverado aren't that large... That would suck.


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## Kellyo77 (Dec 5, 2009)

I covered one of mine completely and half of the other one. The one closest to the exhaust is covered completely. definitely made a difference in cabin noise. No windows blown out or anything like that. It is much quieter inside the truck.


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## txdog27 (Sep 10, 2011)

Probably gonna cover the passenger side one (exhaust side) and then semi cover the driver side one and put foam over it and see if that is better but still usable....


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## Brian Steele (Jun 1, 2007)

txdog27 said:


> Ok so i recently gutted my truck to line the entire inside of the truck doors, back, front, top and bottom, with sound deadener....which is a 2003 Dodge Ram Quad Cab by the way......and I noticed when I pulled off the foam piece that runs behind the rear bench seat that there are two square holes cut into the cab wall with black vent looking grilles with rubber luvers or flaps in them...
> 
> I am guessing these are some sort of pressure equalizers or air exchange vents and are probably there for a reason.....BUT.....what problems would come from sealing over them with dynamat?
> 
> ...


I used to own a Mazda 323 that exhibited some god-awful noise whenever the bass hit. Turns out that it had two flaps in the rear exactly like what you described, and they would vibrate like crazy when I turned the bass up, creating the annoying noise. I replaced the flaps with some open-cell foam and had no issues afterwards.


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