That is weird looking, it almost looks like the mold was filled in where the petcock slides into. The petcock is normally a white nylon part the goes into that hole. And than a hose on the tee part of the radiator drain running along the rail out through the wheel well
Ethier someone tampered with it or GM made the later years radiators cheeper and some what disposalbe, not sure.

 

Here are some pictures of my old radiator I replaced.









It looks like yours is missing the part you turn to open the drain.


edit: stupid photobucket. Don't know why they display so small. But it should give you an idea, at least.

 

Man that blazer is sweet looking!

 

Celestine red's is on the driver side, your picture looks like you're showing the passenger side correct, if so check driver side to see if there is 1 there that's maybe correct possibly dummy 1 on passenger side... Just a shot in the dark...

 

Are you talking about mine? Lol, if you say so! I guess it's not bad considering I only paid $400 for it.

 

Whos ever is on the first page 3rd pic

 

Oh. Gotta use that quote feature, man!

 

Thanks all.
Yea thats on paszenger side, couldnt find anything on drivers side. Those radiator pics look like it, i think your right about the missing peice. Not sure what I can do about it ut ill call discount an see if hey have anything.