Radiator drain plug won't close - @#$^%!

[EarthPig]

Hello everyone, I am new to the forums, and the diesel world. I recently purchased a neglected 1990 F-250 4x4. I decided to flush the radiator since it was running a little hot. After the flush, I was planning on using Prestone radiator cleaner. Fast Forward... the water is running clear. I let the radiator completely drain out, then hand-tighten the drain **** as best I can. Start the water back up to fill the radiator (required for the cleaner) water starts to empty out of the drain. Stop the water. Maybe get an eighth-more turn out of the drain ****. Start water. Leakage. Not just a drip-drip affair either. Full-on pouring out. What do I need to do??? Is there a special tool? New radiator drain ****? Tow to a shop? I feel like the bull in a bull-fight; very confused, pissed off, and helpless!

[pipelayerjdh]

Try cleaning the threads with a small brush and clean the drain ****.