Small issues like slower speed and higher noise may appear after operating the AC fan for a long period, which is probably caused by a lack of lubricating oil in the bearings. Let's adhere to the editor to discover how to lubricate AC fans!
Peeling off the plastic stickers from the fan shaft is the first step. Take care not to completely pull them off to reveal the bearings. It will be more difficult and less likely for the stickers to stick back on if you completely remove them. We can now see that the bearing is dry and devoid of lubricant, and this is what is causing the noise.
After tearing off the label, we can use a small screwdriver or tweezers to pry open the oil seal cover in the center (some fans do not have it), take one or two drops of lubricating oil, and carefully drip it onto the fan bearings. Rotate the fan blades once per drop to ensure that the bearings are fully lubricated. Usually, there is no need to add too much, two drops are enough. If there is too much, it may cause overflow, making it sticky and easy to get dust, affecting the normal operation of the fan.
After adding the lubricating oil, we will install the oil seal cover and stick the sticker back to its original position. Try blowing hard on the fan blades to see if they can operate. If they don't rotate, it indicates that there is still dryness inside, and more lubrication is needed until they are fully flexible to rotate.
