Teared apart the rear interior to prep for some work back there. Noticed there was about 1 sq ft of sound deadener that was stubbornly glued on really well so I started scraping away at it. And eventually I noticed that it was to seal that "random" plug that at the bottom of the well. It was all rusted out so im just gonna weld a clean piece of sheet metal on it but im curious. What is it and why is it there? Below I got a pic of it. Its just bugging me bc I dont know why GM put a, what seems to be, unnecessary hole in there. Any one know?

http://images.filecloud.com/595629/DSC02443.JPG

What?

 

Thats so you can actually fill that area up with ice to keep your beer cold, then when it melts you just take the plug out to drain it.

 

Yup, what he said!
Lot's of GM cars have those in the floorboards and are known to have rust around them.
Not exactly sure of their original purpose though.

 

I have to admit when i saw that im like man i should make this into a a cooler lmao
"Hey guys want a beer" *pops open hatch*

 

I guess the GM engineers are the only ppl that know the purpose of this?

 

my best guess would be that it has something to do with the actual assembling of the car, like where a machine holds onto it or something of the sort.

 

One of my old shop manuals refers to those as "drain holes", go figure.

 

GMs are not the only ones that have those. my old jeep cherokee had them and they ended up leaking and causing the whole floor board to be replaced. they were like 3"circular cut outs with rubber plugs.

 

those are there in case you get water in the car and are designed to be removed to drain it. There are more in the floor pans too...mine also have rust around them

 

Lol if they were designed to be removed to get water out, GM chose the wrong adhesive. I've had to remove 4 of them, and they all successively got harder to remove... either that or my arms just became more and more tired. They're under each footwell/low spot in the car (there are small ones where the rear seats cover). I think their original purpose was as actual drain plugs. For washing it, or coating it in a liquid etching primer or similar. They weren't for hot dip galvanizing, these cars were never hot dipped (or they wouldn't be so well known for rusting). I know I used them to wash my car out. Just popped them all out and squirted everything down with a hose before I began applying the damplifier