Air conditioner repair

The reason why central AC unit makes a squealing noise

HVAC and AC systems make noise while they run and there is no need to be worried about these sounds. Central AC unit squealing is a normal part of the operation and even if you have a “quiet running engine.” The air ductwork can reveal the sounds by adding vibrations and clacks. On the other hand, central AC unit squealing noises that are made by AC system can be unfamiliar to the homeowners, and they do not associate with the regular operation of the AC unit, probably it is the time to call for an HVAC service. These sounds may be signs of some potential issues with your air conditioner system.

On our previous blogs, we have shared the importance of regular AC maintenance. Cleaning and maintaining the AC unit will help the homeowners to avoid possible problems. But what if after all, you hear the central AC unit squealing noise? It is more than probable that you are going to experience it in the spring because the compressor has been sustained to winter components such as ice for three months.

If you hear AC unit squealing noise, you should check three things.

The bearings that are affixed to the AC system condenser fan has to be changed


repairing-central-ac-unitAlmost all modern AC systems own direct-drive motors which means they do not have belts. These types of AC units use a condenser fan to pull the air through the condenser coils that are situated in the compressor.

If your AC unit has a direct-drive motor, you are most likely hear the AC unit squealing noise from the outdoor unit. It indicates that the bearings on the fan motor are broken and you will have to replace them. We highly recommend you to call a qualified technician for HVAC repair. Repairing on your own can result in increasing the damage and more expensive repair.

The belt conjoined the motor to the blower has to be changed

outdoor-ac-unitModern AC units stay away from the belt system. If you use an older unit to cool or warm your house and are informed that the central AC unit is belt-driven, then the problem is related to the belts. Over the years the belts have been used, and probably they have slipped. The homeowner is going to experience the AC unit squealing noise both outdoor and indoor units that are coming through the vents. If it is the real cause, you will have to replace the belts and call for an HVAC specialist.

It is nothing special

AC unit squealing noises are emitted under the regular operation by a lot of AC systems. They have been sitting for a few months and have to work out its cycles at this time in the year. If the AC unit squealing noise lasts only a few minutes, you do not need to worry about it. In typical cases, the AC unit squealing sound is slight and short. If it is louder and longer than a few minutes, in this case, you should inspect other causes.

How to repair the AC units

You can use a motor lubricant and spray lubricant on the motor shaft to relieve the AC unit squealing sound temporarily. But, it is not the permanent repair, and an HVAC repair specialist should inspect and fix the problem as soon as possible.

Other reasons why the central AC unit makes noise

It is possible that you have overworked the AC unit. Generally, AC units are running too hard to remove the humidity in the house. To solve the problem, you can get whole house dehumidifiers that considerably remove the humidity and prolong the lifetime of the AC unit.

Also, there are six common AC unit noises, and maybe you want to know what their causes are:




central-ac-unit-fanThe situation is that the homeowner hears the screaming sound or high-pitched sizzling sound. It is more likely to happen when the AC unit turns on first, and generally, it lasts about 10-15 seconds before stopping. In this case, the AC system can shut itself down and turn on over and over again. The compressor can be the cause of this problem. It is most likely that there is a high strain building up in the system; that’s why it causes the compressor to scream. At this stage, you do not have to keep the AC unit running. It can be disastrous. First of all, turn off the AC unit and call for professional help to fix it. There is a safety switch to turn the AC unit off in these cases, but it can be out of order.


When the outside unit is working, you can hear knocking noise that is coming from the AC unit. The knocking noise does not occur with you turn the thermostat to fan. Probably, the cause is that the fan is crashing something inside of the outdoor unit. It can be an obstacle which does not have to be there or that the fan has got loose from the mount and hits the protective cage. In this case, you have to turn the unit off as well. If you continue to work the unit, it can result in even more significant issues. You should turn the air conditioner off and call for a professional air conditioner repair service.

Gurgling noise

While the AC unit is working, you can hear the gurgling noise. It is tough to tell where the noise is coming from, but probably the condensate drain line makes the bubbling noise, or there is a refrigerant leak in the central AC unit. It is a storm in a teacup, and it is most likely not to hurt anything in the system. You should ensure that the condensate drain line has an accurate trap. If you guess the problem is related to the refrigerant leak, get it fixed by a professional.




When the air conditioner is turned on, a thunderous screeching noise is coming from the outdoor unit. It sounds like a metal on metal. The screeching noise will continue the air conditioner is turned off. The reason can be the broken fan motor bearings. If it is a problem, you will have to change the fan motor. If the temperature is in 100-degree heat while waiting for a maintenance specialist, you can use the air conditioner in this case. You have to get it fixed as soon as possible.

Clicking while the air conditioner is not operating

The homeowner will hear consistent clicking sounds, while the outdoor unit is trying to turn on. The air conditioning unit will not probably turn on, however, it will continue to make the clicking noise. The reason can be an electrical issue that has to be fixed. It can be a malfunctioning thermostat, a capacitor or a compressor issue. You can not use the air conditioner because the unit will not start.

Clicking while the unit is operating

You will hear repetitive clicking sounds from the outdoor unit which is getting faster. A small obstacle in the outdoor unit can be the reason. Before keeping the air conditioner running, firstly, you have to remove the barrier. After that, you can use the central AC unit.