Hello I have noticed that water is leaking from this part of my radiator valve. Would anyone know what this part is called and how I can fix this?
It's this: https://www.screwfix.com/p/drain-cock-15mm/99939 Problem is that the system will need to be drained to replace it or perhaps frozen at that point. Have you tried tightening the square bolt a little? They just have a rubber washer inside.
Yes that it the one. I have tried to tighten it but there is still water leaking. Is it time for a new valve?
Personally I would try to change the washer or swap the works for identical new works by just doing it live, or by reducing the pressure in the system (even if open vented) The rubber washer inside might be stuck though. Plenty of towels and a helping hand needed. If not a ground floor, then risky flooding ceilings below