edmontondown 发表于 2013-1-2 23:56 7 W8 H0 W/ i1 ?9 m y4 wyes, may have something fell down on the other end of the hood vent
; J+ Z- o3 M5 }2 uAt 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.