Gents,
As I recall, most of the older motor homes, class As and Cs, had "Vented" doors on them for the generator cool air intake. Now, that was a while ago and the design engineers have maybe taken a different approach to this issue. Although they, the generators, still need air, for air cooled ones anyway, the engineers maybe think the intake need not be so, should I say, "gaudy" in the form of a vented door, as in the old days. And that maybe what's leading to some of your problems. Just guessing here.
As far as the "clacking" is concerned, can the OP actually hear it while the gen is running? That would be some seriously loud clacking, in my opinion.
I don't recall these types of issues in the older days but, I haven't followed this type of issue at all. So, all I can do is surmise.
Scott