Common AC Problems and Their Causes

Share this post with your loved ones

It’s normal to hear a little sound coming from your air conditioner, but once it makes an odd noise you’ve never heard before, it’s time to perform an inspection. Other indicators that your AC needs to be checked and possibly repaired include freezing and water leaking inside your house. But what could be their causes? Can they still be saved?

Professional air conditioning services in Modesto and other cities can help identify your AC’s problem and provide the right solutions. But for the meantime, you need to know the different problems with ait conditioners, as well as why they freeze and leak water inside our houses.


Modern high-efficiency AC units are made to be quieter, with the compressor’s noise levels kept below 55 decibels. So, if you own the latest model, noises are by all means not normal.

Clicking noises during start-up and shutdown is normal, but ongoing clicking is not. A defective control or failing thermostat could be the cause. If not, there could possibly be electrical issues, so pay attention to those as well.

When you hear a buzzing sound, it could also be an indicator of a loose part, but also debris inside, copper lines rubbing against something, dirty condenser coil, dirty air filter, or freezing up due to refrigerant leaks. Buzzing and humming noises could also point to electrical problems. The humming in the compressor could be triggered by loose wiring.

If it’s a squealing noise, the outdoor fan motors and indoor blower motors could already be going bad. For some units, the sound may be normal, but if you’ve never encountered this sound before in your unit, then you’d need to check the motors.



Dirty air filters and closed air registers could be making your AC freeze up, so check for those two, and make sure that the registers are both clear and open. Other causes could be a low refrigerant and improper fan operation. The temperature of the coils need to be above freezing, and a low refrigerant could make them too cold. The improper fans, on the other hand, could restrict required airflow, and freeze up your coils.

Check on your thermostats and drainage. The drainage could be blocked by the ice in the coils. Debris and twigs could also obstruct the drainpipe, so mind those. A hairdryer can be used to unfreeze the coils in a window-type unit, but if this isn’t an option, call a professional before it leads to more costly damages.


The most common cause of leaks is a clogged condensate drain line. Dust, dirt, sludge, or mold could be the clog culprits. Wet/dry vacuums could help you unclog the drain lines and stop the leakage, but professional cleaners could be the better choice. In units older than 10 years, the leak could be because of a damaged or rusted drain pan, and the pan needs replacement in this case.

If your AC is installed in a basement, the condensate pump that pumps the water outside could be broken and needs replacement. Air filters must also be checked in any kind of unit. Dirty air filters block airflow, and when this happens, the coils get too cold, freeze over, and leak when the ice melts. Note that air filters need to be replaced every 1-3 months. Low refrigerants that cause freezing will also lead to leaks once the ice in the coil melts.

In any case, it is advised that you call a professional for assistance. Trying to solve the problem without expertise could only lead to damages that will cost you a lot more. AC units aren’t exactly cheap, so give them the utmost care and let an expert handle the repair and maintenance.

Scroll to Top