Cabin overpressure "valve"?

I remember seeing a little butterfly valve thingy looking hole that has a little flap on it under the left rear lamp when I had the bumper off, and I assume it's purpose is to let overpressure out when the doors are slammed shut, am I right?

I didn't inspect it more closely back then, so I'm not sure if it is an over pressure valve or something else, but now that I have been thinking about all the spots in the body that need to be sealed up in order to keep all the mud and water outside when I sink the truck into some bog, I think that hole needs to be sealed too if it leads inside the cabin. So have anyone done anything to it, and would it be bad for the door seals if there is no pressure relief hole? It's my first truck that I might be able to make water tight, so I haven't thought these things thoroughly yet! :laugh:

Also what is the purpose of those two little about 1" holes in the both sides of the body in the rear corners, also found under the bumper? I had some major rust around the other hole, and I've been thinking about welding them shut when I have the bumper off the next time.

I could find answers to all these if I would go and get the bumper off, but I don't feel like doing so just now, so that's why I'm asking(and also to help someone else).

I'd wondered the same thing about that flap! An over pressure valve seems as good an explanation as any!

Most of the other holes are drains to stop the body filling up with water. The down side is the flow of water tends to make them rust!

Si

yes that little flap is so you can actually shut the doors properly, without it the door wouldn't shut properly as it would hit a buffet of air just before it fully closes that will hold it open that flap gives the air pushed into the cabin by the door somewhere to go.

but i would get it replaced with something more dust proof as if you drive on dusty roads allot it allows allot of dust into the car as its not a perfect seal when its flapped down

Mines alot bigger than 1'' square! If im thinking of the same thing - under the rear lights and behind the bumper corners the flaps are about 4'' x 2'' with rubber covers.

blakey2000 wrote: yes that little flap is so you can actually shut the doors properly, without it the door wouldn't shut properly as it would hit a buffet of air just before it fully closes that will hold it open that flap gives the air pushed into the cabin by the door somewhere to go.

but i would get it replaced with something more dust proof as if you drive on dusty roads allot it allows allot of dust into the car as its not a perfect seal when its flapped down

I've been thinking about this more, and I don't think sealing that hole would cause much problems. There still is the ventilation system that has air passage out of the cabin to release overpressure out. Unless you have the knob on cabin air re-circulation setting. Otherwise the pressure surely will get out through the vents.

Conclusion: I'm gonna seal every hole I find!

Smoggy wrote: Mines alot bigger than 1'' square! If im thinking of the same thing - under the rear lights and behind the bumper corners the flaps are about 4'' x 2'' with rubber covers.

Yeah, that's the pressure relief hole.

By 1" holes I meant the round ones in the sides of the body.