How To Troubleshoot Rattling Window Air Conditioners

Air conditioners are prone to noise, especially old ones. You may be tempted to dismiss air conditioner rattling or vibration as a minor annoyance, but it could mean serious problems with the unit. Ignoring the problem may eventually cause damage to the fans or motor. 

Many air conditioner noises can easily be traced and fixed by a DIY person, which saves money on costly repairs or a new unit. Learn how to stop the rattling by following these suggestions.

Check External Causes

To fix the noise, you need:

  • a rag
  • cleaning spray
  • cellophane or foam pad
  • screwdriver or adjustable wrench
  • scissors
  • wood shims (optional)
  • outdoor caulk and caulk gun

Improper installation is a common cause of rattling. Turn the unit on, and push it further in the window, or hold it steady on the wall. If the noise stops, it means the air conditioner needs to be better secured to the window. 

To seal a gap, cut a piece of foam or cellophane to fit into the space between the unit and wall. You may also use wood shims to fill in gaps between the unit and the sill. If it has shims already, readjust them, and try running the unit again.

Sometimes, the issue may not be with the air conditioner, but the window. Push around the window glass and wooden frame to check for loose glass. If the glass seems loose, add a bead of caulk around the glass pane edges, and let it dry.   

Inspect the outside of the unit for debris, such as twigs and leaves. Dampen a rag with the cleaner, and wipe the outside of the air conditioner. 

Troubleshoot Internal Causes

Disconnect the power cord to the unit, loosen the screws or bolts on the casing, then carefully lift the casing from the unit. Look for the air compressor, which is a cylinder-shaped part on the rear of the control panel.

Occasionally, the manufacturer may tighten the compressor bolts or screws too tight to keep the unit steady during shipping. Use a wrench or screwdriver to turn the hardware slightly left. Consider getting it replaced if that doesn't help. 

Find the refrigerant tubing that transports the coolant, which is usually copper. It may have gotten bent or installed too close to other parts. Try to unbend the tube, or push it back in place.

Inspect the fan blades, and ensure they are clean and unbent. Grease and bent fan blades may throw the unit off balance. Remove the grease, and straighten the fan blades.

To learn more, contact a company like Vets 4 You Plumbing Heating & Air