had the same problem just rip it off since your replacing it anyways trust me you wont break anything. when done get a new clamp just put a clamp with a screw on it. the style that you can loosen and tighten with a screw driver. no idea what thats called sorry. but thats what i did. and havent had that coolant problem since now i just burn coolant and spit coolant out of the resivior
ugh if you know what or how to fix would be nice ty