A Squeaking Sound From an Air Conditioner

Fan Housing

• If the noise only occurs during operation, the fan might be to blame. An improperly installed fan might nick the side of the fan housing as it turns, which produces an annoying noise and limits the power of the fan. You can remove panels to the air conditioner unit to get to the fan component, but before you do so, the power should be turned off to prevent electrocution. If you give the fan a good spin and see that it doesn’t turn freely and hits the housing, the fan should be uninstalled and reinstalled so that it clears all obstacles when blowing.

Ball Bearings

• Squeaking can also occur when the fan’s ball bearings aren’t oiled or are dirty. The fan should be properly lubricated to avoid rusting or stunted operation. After the panels to the unit are removed and the power is shut off, give the fan a spin. If it fails to spin freely and the fan clears the housing, the ball bearings might need to be lubricated. You can insert electric motor oil into the bearing lubrication ports to lubricate the bearings. Spinning the fan around a few times helps to distribute the motor oil. You should notice the fan spinning freely.

Duct Work

• Improperly installed duct work might vibrate and simulate a squeaky noise as it vibrates and rubs against itself or the wall during air conditioner operation. You can access the duct work at the point of the squeak and either replace old, faulty duct work with new or secure the duct to a wall with wire or tape. Test the secured duct work by turning on the air conditioner to cool mode and its highest fan setting.

Window Installation

• Sometimes air conditioner noise from a window unit is owed to improper installation, which can be remedied with unit removal and reinstallation. Pad the windowsill and sash with weather seal to prevent the unit from making direct contact with the window frame. Weather seal comes in strips or in a roll. A paper backing can be peeled from the weather seal to reveal a sticky underside. Press strips of weather seal to the windowsill and sash and the unit installed between the two to prevent the metal cabinet of the unit from scraping against the metal windowsill during operation.