cabin heater muff

Thanks, Matt! Makes sense

Don

without the scat tube hooked up, there was nothing to dampen the vibrations,

Three years ago I installed a cabin heater muff on the exhaust system to protect the other engine parts from the heat of the exhaust, but I never hooked up the heater itself. The two openings of the muff I left open. Recently I discovered that the outlet that would have led to the heater box had broken off and taken a small piece of the shield itself with it. I am curious as to why this happened. Could it be that without the air flowing through the muff that would have taken place had I run tubing from the opening through the engine baffle, the muff became too hot? Otherwise I am at a loss.