My evaporative (swamp) cooler's front grill (part within the house with vents, controls, etc.) vibrates noisily making a loud annoying buzz after the cooler runs for several hours. If I press hard on it then it is silent. I tightened the four screws holding it to the cooler, replacing one of them, but no help. I suppose something in the cooler blower ot shroud is silently vibrating but I can't locate it.
I suspect removing the grill would be difficult due to the wires to the controls.
Probably hopeless but any suggestions?
TIA