I cleaned out the screw hole and piled the jb weld in, then put it all back together before it dried. I ended up with the plastic cover piece somewhat jb welded on, but with a little force it popped free of the radiator when I installed the new radiator. Jb weld really does not bond well to plastic.

 

A nylon zip tie melted and dripped in there can also be a field fix. Maybe swab with acetone or spray with brake cleaner to remove any grease. The radiator design "saved" a bracket, but added a stress point. On a vehicle intended for a lot more than a bunny hop on the trail....

 

Seriously, the coolant change did not cause your leak and if the radiator is leaking, buy a new one, do not risk a short term fix on your engine.

 

i jbweld plastic all the time with great results.

 

I had the same leak the day after I bought my Disco. It poured out a bunch. I cleaned the hole with brake cleaner and filled it with JB Weld and screwed it back together. It leaked the next day after getting warm. I then cleaned it out again and filled it with Black RTV making sure to press some into the hole so it would fill the crack in the wall and it has not leaked since. I filled it, and added RTV around the screw and it's head and the bracket that goes over it. It's been months and still holding well. I will at some point replace the radiator, but for now, I just watch it.

The screw is not too long, it's a poor design of the Radiator. Inside where the screw is the walls are very thin and it basically splits along the screw.

Check THIS POST and see the photo that shows it inside.

 

You are both right and wrong Mike. Correct, the change didn't cause the issue, but the clotting properties of the Dex when exposed to air kept it at a minimum. I could tell ever so slightly by looking at the bottom of the truck there was a pink leak before, but not enough to notice. Flushing the system took the crust and clotting away, so it is free to leak the Ecto juice now.
I was half kidding with the title...but what it did was take a "would be nice to fix" and turned it into a "must fix".
My big question now is, can I swap the one from my 00 into the 04? Everything looks the same, but on some sites I see some different part numbers. I know on the 00 there is a drain plug and on the 04 there is a sensor there, but looks to me like the same hole. Anyone know?

 

So on that inside picture, I'm assuming the hole in question is the one up on the left side of the picture, right? So if you put the JB or something like it in, it won't actually flow into the radiator, right? In theory, you should be able to stuff that hole up good and be done with it?

 

I stuffed it up good, but if you stuffed it TOO much, yes, it's possible you could push enough through to break off inside and it's directly into the coolant. That crack you see on the left is inside the top of that plastic SIDE of the Radiator. It's laying down in the photo.

Yes, it CAN get into the Radiator, so use common sense when you fill it.

I filled it, pressed a LITTLE bit more in so it would enter the crack, placed more around the top of the screw hole, dropped the bracket on, placed a little more in the hole in the bracket, screwed in screw firmly but gently as to not spread the threads and widen the crack, then wiped the screw off leaving any extra around the bracket, let it dry, and voila.

 

OK... I went with plan B for now and so far so good. Put in K-seal and let it do it's thing. I then flushed the system as I didn't have a need to have the stuff in there, and flushed it good. The leak is sealed... worked like a charm. Drove around for a while and all good, and temps on Ultra Gauge were the same. I took out the stat to check and make sure it didn't get plugged up and she was totally clean. Nothing left in the expansion tank either. I have to say that stuff does exactly what it says. At the least it will buy me a couple weeks to drop in the new radiator.

 

I know you will be extra careful around the fan.....