Air conditioners aren’t always the quietest, and this is especially true for older units. However, while you will generally always be able to hear your air conditioner running, it shouldn’t make any loud noises like squeaking or squealing. If your AC is making any unusual or loud noises, it is usually a sign that something isn’t working properly, and you need to have the system repaired. With this in mind, let’s look at the most common AC issues that can cause squealing noises and what you can do to fix them.

Belt Is Worn Out or Misaligned

If your AC is making squealing noises, it may be that a belt is damaged, worn out, or misaligned. This is similar to the squealing or squeaking noises you often hear in older cars.

While newer AC systems are usually direct drive, many older ACs are belt driven. The belt connects the motor to the fan and transfers the energy so that the fan spins whenever the motor is running. Depending on the age and type of AC, you may have a belt that drives the blower fan inside the building as well as another belt that drives the fan in the AC compressor outside. If the blower fan belt is the issue, you will hear the squealing noise inside the house near the air handler and also coming through the vents. If the issue is with the belt in the AC compressor, you will usually only hear the noise outside or coming through the walls in those rooms near the compressor.

Over time, the belt can start to fray, stretch, or become worn out. The summer heat and humidity can also cause the belt to expand and become misaligned. When any of these issues occur, the belt will start to produce a high-pitched squealing noise. In this situation, your only option is to replace the belt. While you may be able to replace the belt on your own, it is still always best to have a professional AC technician do it for you just to be safe. This is especially true for the AC compressor belt as you could easily damage the compressor unit, which could lead to much more costly repairs.

Bearings Need Oiled or Replaced

Newer direct-drive AC compressor units use bearings instead of a belt. When these bearings get worn out, they can cause a squealing noise similar to when the belt wears out. It may also be that the bearings are still in good shape but aren’t well enough lubricated. Most ACs use sealed bearings that don’t ever need lubricating, but there are some units that do need to be oiled occasionally. Whether the bearings need oiled or replaced, it is important that you hire a professional AC technician to fix the issue so that you don’t risk damaging or ruining the compressor.

High Pressure in the AC Condenser

If the refrigerant pressure inside the AC compressor is too high, it can also cause a loud squealing, screeching, or hissing noise. This problem is usually most noticeable when the unit first turns on and will typically subside within 15-20 seconds. You may also hear the same noise for a few seconds whenever the unit shuts off. High pressure will often also cause the compressor unit to turn on and off more frequently than usual. If you do notice this issue, you should immediately turn off the power to the unit and leave it off until you can have it inspected by an AC technician.

There are a number of potential reasons why the pressure is too high, such as a refrigerant leak, dirty condenser coils, or a faulty fan motor. No matter what the underlying cause is, it is important that you don’t attempt to use the unit until the issue is fixed. Running the unit when the pressure is high can potentially burn out the compressor, and the only way to fix this is to replace the entire unit.

Other Noises to Watch Out For

Your air conditioner can also make a number of other unusual noises that can also indicate an issue with the system. One of the most common issues is hearing a rattling, buzzing, or humming noise coming from the AC compressor, and this can have many different causes. The noise could indicate that the compressor fan motor is worn out and needs to be replaced or that the motor is no longer balanced. If the motor is worn out, the fan blades won’t spin when the compressor is on. This can cause the entire unit to vibrate and create a loud rattling or buzzing noise.

If the fan blades or any other parts of the compressor unit are loose, it can also cause a rattling or buzzing noise. This same problem can also occur inside the building if the blower fan blades are loose or if the air handler or blower fan isn’t properly balanced.

Alternatively, the same rattling or buzzing noises can arise if the rubber “isolation feet” are old and worn out. Over time, the rubber can become cracked or start to disintegrate due to exposure to heat, cold, and moisture. When this happens, the unit will become unbalanced and start to vibrate and make noise.

Your AC compressor may also start to make a loud knocking or banging noise. This usually indicates that something is obstructing the fan blades, such as a stick or other debris. To check if this is the issue, simply shut off the compressor and inspect it to see if there is anything inside it that could be obstructing or interfering with the fan blades. If the fan blades are clear and the noise persists, you’ll definitely want to get the unit checked out by a professional as soon as possible.

Air conditioners can also sometimes make a bubbling or gurgling noise. The most common reason this occurs is that the condensate drain line is clogged, backing up, or otherwise not draining properly. This issue is usually fairly easy to fix on your own by unclogging the drain line. However, if the drain is seriously clogged, you may need professional help.

You can also check to see if the system is draining properly by opening up the air handler unit to see if there is standing water in the drain pan. You could also try to pour a bit of water into the drain pan to see if you can hear the gurgling noise as it drains.

The same bubbling or gurgling noises can also occur as a result of a refrigerant leak. In this case, you will need to have an AC technician seal the leak and then put more refrigerant back into the system.

Expert AC Diagnostics and Repairs

If your AC system is making any loud or unusual noises, the highly trained, expert technicians at Honest Air Conditioning can diagnose and repair whatever issue is causing the system to make noise. We work on all models and types of AC units, and our technicians have years of experience fixing any and all AC issues. If your unit is more than 15 years old, replacing the unit often makes more sense than repairing it. We are a Carrier dealer and can help you choose the right size and type of replacement unit to ensure your cooling needs are fully met. We also specialize in AC maintenance, which is the best way to prevent the most common air conditioning issues.

Stop dealing with the frustration of a noisy air conditioner in Mesa, AZ. Instead, give us a call today to enjoy the quiet home comfort you deserve.