An air conditioner that produces noise every time it runs can be quite irritating. This, in addition to the fact that the noise may be an indication of a significant-enough-to-damage-the-unit problem, makes it imperative for you to not only trace the source of the noise but also fix it.
Rattling noises coming from window air conditioners are usually as a result of problems with the system's fans. Here is what you should do once your unit starts making these sounds.
Look for unwanted materials and get rid of them
Your home's insulation can find its way into the window unit. If the air conditioner is located near an area with vegetation, leaves and other debris can also find their way into the unit. When this happens, the air conditioner's rotating fan may end up hitting on the unwanted materials every time it rotates. This may then cause an irritating rattling noise.
Start by opening the unit's cabinet and locate its fan. If there is any debris around the fan's blades, remove it. Wipe the blades with a wet rag to get rid of any dirt and traces of insulation. After you are done, close the unit and run it. This is usually enough to solve most rattling noises.
Look for a loose blade and tighten its screw
If the debris removal process doesn't do the trick, then you are likely dealing with a loose fan blade. In such cases, since the blade doesn't have a firm base, any rotating motion is likely to make it move in a jerky motion. The increased vibrations that result because of this not-so-smooth rotation may then be what is causing the noise in your air conditioning unit.
What you will need to fix this problem is a screwdriver. Use the screwdriver to tighten the screw that is located at the hub. Doing so should be enough to eliminate the jerky movement and thus eliminate the irritating noise.
Check for bent blades and straighten them
When a fan's blades are bent, they usually end up knocking on the sides of the housing on which they are located. The air conditioner is therefore bound to produce rattling noises every time the fan rotates. This is a problem that is usually solved by simply straightening out the fan's blades.
A fan whose blades are dirty, loose or bent can't rotate as well as it should. This not only produces irritating noises but also affects the air conditioner's ability to cool a given space. It is therefore advisable that you get your air conditioner fixed as soon as it starts making rattling noises.