Droning Exhaust on Flxible Metro and Other Buses

[ClassicBusFan1981]

Hi,

Is it true that the terrible droning noise heard in the exhaust systems on Flxible Metros as well as Ikarus/NABI, Gillig, Orion and some New Flyer buses is linked to one of the following issues below?

The hot sheet:
*Exhaust system resonance (95% probable)
*Loose fasteners, broken mounting brackets or hangers; system grounding
*Loose parts in muffler or catalytic converter
*Alternator or air pump mount

Thank you,



Ben Edge