[MOTORHEAD]

I don't know how you managed to UN screw it INTO the radiator, but obviously you'll have to drill & tap to the next larger size and that will give you a bit bigger hole to work through. I would say just leave it in there,but it might get pushed over to the bottom hose neck by the water flow and road vibration. That is also a bigger hole to work through. Maybe a air blow gun with a flexible hose on the end might blow it over to the bottom hose neck.