It has always annoyed me that draining a radiator is usually a fairly messy process. I just got a new radiator for my '64 Nova, and decided to fix the draining problem before I installed the radiator. The normal drain cock screws into a threaded hole in the bottom tank of the radiator. The drain cock is brass, and has a hollow threaded plug with a hole bored in the bottom of the plug shaft that allows the coolant to drain out when the plug in unscrewed until it stops.
What I did to make life simpler was to remove the drain cock assembly from the radiator. The hole in the drain cock shaft where the water flows out of is just a wee bit larger than 1/8". When I say a wee bit, I mean a few thousandths of an inch. So I went over to Lowe's and bought a 6" brass 1/8" diameter tube, then cut 1 1/2" off of it, smoothed and rediused the cut end, then clamped the drain cock hex nut in a pair of vise grips to hold the whole thing steady. The hole in the bottom end of the plug is 9/64". That's important. When I test fit the brass tube into the drain fixture, it went all the way to the bottom of the hollow threaded plug, which blocked off the drain hole. I screwed the drain plug in until it stopped, then put a 9/64" drill bit through the hole in the drain plug.
Then I put a little soldering flux on the bottom end of the brass tube, put it into the drain plug, and used a soldering gun to solder the tube into the drain plug. I wasn't sure that a soldering gun would get the brass drain plug hot enough, but it did (if it hadn't, the next step was a propane torch). I soldered the brass tube all the way around. Once the solder set up and cooled, I took the drill bit out, then inspected the plug for air holes, and there weren't any. The drain plug moved freely and closed properly when screwed in or out. The brass tube extends out of the drain plug assembly about 5/8", which I think is just about the right distance.
After applying teflon tape to the outer threads on the drain, I screwed it back into the radiator tank, and now when and if I need to drain the radiator, I can plug a rubber hose on to the brass tube and drain straight into a bucket or empty gallon jugs. Simple, easy, and efficient.
