Yes, how dare you tell me that a cheap option that you can do, that
would meet my requirements, is WRONG!
I'm not telling you how to do the plumbing. A plumber may present me
with my options, and I would select one, based on price and likelyhood
of it removing the noise.
I'll leave the actual plumbing to the plumber.
I do appreciate the good posters in the newsgroup that have suggested
alternative options, and , if I find that there is no noise after
removing the radiator, I will consider having it put back and persue
those alternatives mentioned, by hiring a person skilled in hydronics,
to do the job.