What Causes Your Outside Air Conditioner Motor to Run Loud?

Debris

• A fan could make a huge ruckus if debris has fallen or been inserted into the intake grille. Trash, such as plastic bags or string, could have made its way to the fan motor and jammed up the gears. This causes the fan to stop turning while the motor continues to work and creates a loud noise. The fan could be only partially blocked and struggle to turn. After power to the unit has been turned off, you can remove air conditioner panels to access the fan housing and remove the debris.

Housing

• If the condenser fan is installed incorrectly, the fan strikes the fan housing and causes a clatter. The fan could be completely stuck on the side of the housing, causing it to stop turning while the motor noisily continues working. Leaving the fan impeded too long could damage the fan motor. After panels are removed to access the fan housing, uninstall the fan from the motor and remount it the correct way. Give the fan a swing to confirm that it clears the housing.

Ball Bearings

• Gummed-up or dry ball bearings can cause a clatter within the fan motor. Not only is it noisy, it creates unnecessary resistance on the fan axle, causing the fan to turn slower than normal. Once panels are removed to reveal the fan housing, swing the fan around. It should spin freely. If it doesn’t, the bearings need lubrication. You can apply electric motor oil into the lubrication ports at the base of the axle and spin the fan a few times to work the lubrication into the bearings.

Motor

• The fan motor may have suffered some damage from debris or a blocked fan at some point, which causes it to permanently run noisily. The fan components could be fixed individually, but it might just be cheaper to replace the motor. To avoid further damage to the fan motor, you should cut off the power at the circuit breaker and call a technician to determine the next step.