Fixing a radiator mount tab?

Probably soldered. To fix properly, need to take the radiator to a good radiator shop and have it repaired. Might as well have it inspected and cleaned internally while it is there.

 

I agree, it's soldered on.......

 

This could be fixed on the car. Just need to drain enough fluid so a couple of inches at the top have no fluid. Then remove the bracket to clean, flux and tin the bracket underside and the radiator. Put the bracket in place but loose to fit tight on the radiator. Heat up and sweat solder in place. Tighten, clean, paint and refill and you are done.

Easy job to do by yourself, or in a radiator shop. Of course, if you have had over-heating issues, this is a good time to have the radiator rodded or re-cored as needed.

 

I agree with the above, but.....I'd take it to "the man".