edmontondown 发表于 2013-1-2 23:56 4 B Y/ O6 m+ p. U+ m1 V
yes, may have something fell down on the other end of the hood vent
& V' S+ T7 @5 a1 \; K
At the other end(outside) of the vent duct, there is usually a metal cover for the opening, it can swing up and down and if it is a windy day, it will be blown swinging, thus making a kind of banging noise.