I’ve done this trick about 3 times now, on three different vehicles. Taught to me by an old friend who’d done it several times himself.
Leaking radiator tank? Go get some Devcon 2 ton epoxy, and seal it up. Stuff sticks great, and has a great heat tolerance.
Couldn’t get the Devcon this time, so I got good old JB Weld. Famously good stick, and package said a 500°F rating…
We shall see!
(early 90s Subaru)
(Yes, that’s a plastic tank. Man, do I miss the old aluminum or copper tanks! )
The fix (still wet/uncured);
Might take a little trim sanding to clear the radiator cap, but I think it’ll work.