Do I need to remove the drain-plug completely to drain the radiator? I can only turn the drain-plug 1/4 turn in either direction and no coolant coming out. There seems to be something inside to prevent it from turning more. I also try to pull on it with my hand and it doesn't seem to come out. Any help will be greatly appreciated.

 

No you don't have to remove the plug completely. It is best though. Try some WD-40.

 

You don't have to remove it completely, but it can be removed. Seems like it had to be lined up correctly to remove it. Sorry I can't be more descriptive, but it has been a while since I have had to drain my truck. I was glad I did take it out completely because there are spots for two O rings and mine only had one on it. I added a second O ring to mine. I assume the second O ring is functional.