Its the plastic tube that sticks out of the neck and feeds the overflow bottle. Can I get by without an overflow tube if I clamp it off with a hose clamp until I can get a new one? I'm going to Home Depot and Napa to see if I can fix it somehow, but need a backup plan

 

try a automotive shop there is special glue for fixing plastic radiators/ tanks

 

Might work but it's pressurized so dunno.

 

I used jb weld on it last night. Its only pressurized if the radiator overpressures and opens the relief valve on the cap.