A loud bathroom exhaust fan ruins the peace and quiet usually desired while using the rest room. Worn-out parts and vibration create noise in a bathroom exhaust fan. Many times, loose mounting screws or retaining springs cause the noise. Excessive wear causes squeaking fan motor bearings. You should replace a bathroom exhaust fan's motor if its bearings howl or have excessive play. Small adjustments to the fan's housing or motor brackets often quiets the rattling in the bathroom exhaust fan.
Set up a ladder below the bathroom exhaust fan.
Turn on the fan.
Climb the ladder and listen to the noise without touching the fan. If the noise sounds like a squeaking fan motor, turn off the fan and replace the fan motor using the fan manufacturer's instructions. If the fan rattles, touch the louvre with your finger. If the rattling stops with your finger on the louvre, tighten the louvre's retaining device. If the rattling does not stop, tighten the loose part inside the exhaust fan.
Turn off the exhaust fan.
Remove the exhaust fan's louvre. If the louvre uses a retaining nut, remove the retaining nut with the correct hex-head screwdriver. If the louvre uses a set of retaining springs, move the louvre away from the ceiling and compress the springs. Pull the louvre away from the exhaust fan.
Spin the fan motor's blade and listen for a rattle. If the fan blade hits the exhaust fan's back-draft damper, remove the fan motor and adjust the back-draft damper as needed. If the motor's shaft moves side-to-side or horizontally, replace the motor -- an exhaust fan's motor will have a small amount of in-and-out or vertical play.
Grip the fan motor's mounting bracket and wiggle the bracket. If the bracket moves but the housing remains still, tighten the fan motor's retaining bracket with the correct screwdriver. If the plate the fan motor's mounting bracket connects to moves but the fan housing remains still, tighten the tabs holding the plate against the housing, using a slotted screwdriver. If the exhaust fan's housing moves while moving the motor's mounting bracket, tighten the housing's mounting screws with the correct screwdriver.
Apply a piece of foam weatherstripping around the perimeter of the exhaust fan's louvre.
Replace the bathroom exhaust fan's louvre. If the louvre uses a retaining nut, hold the louvre against the ceiling and tighten the nut with the correct screwdriver. If the louvre uses retaining screws, compress the springs and insert the ends of the springs into the grooves on the sides of the housing. Push the louvre against the ceiling.
Applying oil to a squeaking fan motor often quiets the motor temporally. The squeaking will return shortly.