In the process of a resto. But everything together and then I turn it on, one of the burner makes this sound. Best I can explain it is it sounds whistling/metal expanding sound. I had already cleaned the manifold and valves. No smell of leaking propane. Flame looks consistent like the other burners. Before I go the easy way and just replace this, anyone have any thoughts? I don’t see any apparent damage on the burner. But there is some rust around manifold end of the burner.