grinding pipes

Aliza

In response to the banging (and leaking) radiator in my bedroom the building superintendant tightened a loose pipe and changed a valve. While the leaking has stopped and the banging has been minimized (it still bangs fiercely when the heat is first turned on - is this normal?)the new valve has an unnerving high pitch whistle and the standing pipe makes grinding noises throughout the heating cycle. The bathroom standing pipe is making grinding noises as well. Will a new valve stop the whistle or should something else be done? What can be done about the grinding pipe sounds?

Thanks!!!