try some loctite 587 or something, also known as ultra blue. then again a tube of that would probably cost as much as a radiator from the wreckers. Call around and see what they have. Maybe do some searches on the net to find what other car has the same radiator. Or even easier.. goto a radiator shop with radiator and just say i dno what this is out of its off my home made buggy but i need a replacement the exact size, then he will look in his book and tell u oh a vl commodore is the same.. etc.