What to Do If Your Air Conditioner Is Grinding or Squeaking

Two HVAC repairmen working on an AC unit outside of a home

Your home's air conditioner is like any other piece of household equipment in that it can wear out — parts of it break down or fall apart. This can happen because your air conditioner has reached the end of its usable life and needs to be replaced, or it may happen because a single component has failed. In either case, there will be certain symptoms that may manifest in the form of strange noises.

 

The kind of noise your air conditioner emits can indicate the nature of the damage. Grinding suggests a different set of issues from squeaking or squealing. Let's take a look at some of the possible causes.

Causes of AC Squeaks

  • If your air conditioner is an older model, it may have a belt drive. Belt drives are notorious for slippage, which happens because the belts are loose and worn. The slippage can often cause a squeaking or squealing noise similar to the sound made by a car's slipping serpentine belt. In some cases, it may even be best characterized as a kind of scream. The remedy here might be as simple as replacing the old belt with a new one. If you don't replace the belt and keep running the air conditioner, you could be looking at serious repairs as the belt comes into contact with other parts within the air conditioner cabinet and causes damage. In the long haul, you should look at replacing a belt-drive air conditioner with something more modern.
  • Your air conditioner's fan motor may also squeak because it needs lubrication. This is a relatively minor maintenance issue that you may be able to rectify yourself but you should still have a technician check it out in case there is a larger issue.
  • These noises can result from dirt and debris building up on the fan blades inside your air conditioner. Accumulated dirt on the fan blades unbalances the fan and causes it to squeak. If a buildup of dirt is the source of the squeaking noise, the solution will involve opening it up and cleaning it thoroughly.
  • Minor bends to the fan blade may cause unbalancing issues, which can cause it to squeak.

Causes of AC Grinding Noises

  • Abnormal grinding noises coming from any kind of machinery typically indicate metal on metal friction and it's always a bad sign in any mechanical device. Two components are rubbing against each other when they shouldn't and this means that there has already been a major failure or that one is on the way. When it comes to your air conditioner, the grinding noise is often a sign that bearings in the unit's condenser fan motor are failing. This motor powers the fan that pulls hot air out of your home and pushes cool air in. Failed bearings can occur in newer air conditioners that have direct-drive systems instead of the belt drive system. If the bearings are failing, you could worsen the damage if you continue to run your air conditioner. Turn it off!
  • A direct drive air conditioner may also make a grinding noise if it needs to be lubricated.
  • If the grinding noise is coming from the compressor itself, it may indicate an issue with the pistons that are supposed to compress the refrigerant. In this case, it could mean that your compressor needs to be replaced or that you need a new air conditioner.

Yearly air conditioner maintenance can prevent the issues that cause your air conditioner to make squeaking or grinding noises. If you are in St. Lucie or Martin County, Florida, contact us immediately to schedule an appointment.