I wouldn't weld up that hole. Just put a rubber plug in it.

 

It's super small. My problem is that the firewall is already painted. So welding it will screw up that area.

 

Various size plugs are available from Home Depot (metal) or LMC truck (plastic).

 

While we're playing the identification game....I believe this hole is for a door jamb rubber bumper. Is it me or is my example cut out extra big for some reason?

 

Yes but you are correct, door bumpers. But yours looks like someone tried to pry the old bumper out with a small screwdriver. They are odd shaped but they normally come right out with a broad blade or even by hand if they have been removed once. Getting them back in is a little trickier and requires some patience but the should be pushed in on the rubber not prized in.

You will need to straighten that metal out or the bumper will not stay in place.


You can zoom in to see the shape of the 2 bumper openings.