We used to own a Mazda 1000 bakkie, which was retro fitted with an unopened A14 engine. At some point the rear welsh plug rusted through, and there was no time to remove the engine and replace it. We poured a packet of curry powder down the radiator to seal the hole. Curry powder will apparently only cook and cure when it comes into contact with air, so it'll clog around the hole and seal it. Worked like a charm, and we used this same remedy probably 3-4 times over a period of many months, until the time came to rebuild the engine. We would know when to add curry powder when you could smell the curry inside the cabin, which meant there was another hole that needed pluging. The welsh plug disintegrated into a lump of rust and curry powder when we took it out. For the ramainder of the time we owned that bakkie, you could smell curry whenever you checked the water levels...