collector noise

[76bonanza]

My header collectors have always been somewhat noisy pinggy and tickey but since the air has gotten cold it seems loader? Does this seem right they are not leaking have aluminum seals and are good and tight. My friend who is a mechanic says the header will make some noise at the collectors be cause they are thiner then manifolds. But do you guys think the cool air will make it more pronounced?

Thank for any advice.