The first thing you should do if your air conditioner is making a grinding noise is turn the unit off at the thermostat.
Air conditioners do get louder as they age, but a grinding noise is never normal—and always a sign that something has gone wrong.
Turn It Off—Yes, Even in the Arizona Heat!
Of course, air conditioners always seem to break down at the worst possible time—like when it’s 110°F in Phoenix, and you need it most!
As I type this from Magic Touch Mechanical’s office in Mesa, AZ, it’s just about 110° outside. So yeah, I know you’re hesitant to shut off your AC…
But if your unit is making a grinding noise?
Go turn it off right now. Then come back and finish reading this.
Why Shutting Off an AC Making a Grinding Noise Is So Important
Since we’ve established that a grinding sound is never normal, we know something inside your AC unit has gone wrong.
And often, a major failure (like a bad compressor) is caused by a minor failure that went unnoticed or unaddressed.
That’s one reason regular air conditioning maintenance is so important (but we’ll save that for another blog post).
What AC Components Can Make a Grinding Noise?
To understand the cause of the grinding, let’s go over which parts in your AC system move—because the noise is usually coming from a moving part.
🔧 Components Most Likely to Cause a Grinding Noise:
1. Condenser Fan Motor (Outdoor Unit)
Also known as the outdoor fan motor, this is located in the condensing unit outside (or on the rooftop, if you have a packaged unit).
Look through the top grill of your outdoor unit, and you’ll see the condenser fan.
Two common causes of grinding noises:
- Worn bearings inside the fan motor
- Broken fan blade rubbing against the cabinet or motor
What does it do?
It expels heat from inside the home to the outdoors and helps cool the compressor.
2. Blower Fan Motor (Indoor Unit)
Also known as the indoor fan motor, the blower fan is located inside your furnace or air handler (usually in the attic, closet, garage, crawl space, or basement).
If you have a rooftop package unit, the blower is still in the rooftop unit.
Two ways this motor can create a grinding noise:
- Worn-out motor bearings (less common than condenser fan issues, but still frequent)
- Broken “squirrel cage” blade or loose mounting bolt causing it to rub against the housing
What does it do?
It moves conditioned air through your ductwork. When you feel cool air blowing from a vent, thank the blower motor.
3. AC Compressor
The compressor is the heart of your air conditioner. It pumps refrigerant through the system and converts it from liquid to gas repeatedly.
Grinding or grinding-like noises from a compressor may come from:
- Failing internal valves, or
- Internal mechanical issues, like damaged scrolls or pistons
Not everyone would describe it as “grinding,” but I’ve heard that description used by many homeowners. (Describing sounds is subjective—just try describing what a violin sounds like.)
Tech Tip:
Sometimes people think the reversing valve is grinding. This component switches your heat pump between heating and cooling.
It makes a quick sound during startup or shutdown—but if the sound is constant, it’s not the reversing valve.
How Do You Fix an Air Conditioner Making a Grinding Noise?
I write blog posts like this to help homeowners in Phoenix, Mesa, and surrounding areas make educated decisions about home comfort and repairs.
But let me be clear:
I don’t recommend trying to fix this yourself.
In 28+ years of running Magic Touch Mechanical (and another 10+ years as a tech prior to that), I’ve seen too many “handy” homeowners—and even Cousin Larry—turn a simple AC repair into a full system replacement.
If your AC unit is grinding, call a licensed, trained HVAC technician. You’re better off letting a pro diagnose the issue correctly.
Now at least you’ll know what your tech is talking about when they explain the issue.
What Does It Cost to Fix a Grinding AC Unit?
There’s no single answer here—too many variables. But I can give you a ballpark range based on the thousands of HVAC repairs we’ve done in Arizona homes.
| Component | Average Cost Range |
|---|---|
| Condenser Fan Motor | $400 – $1.200+ (variable-speed motors on the high end) |
| Blower Motor | $500 – $1,500+ (OEM and variable-speed motors cost more) |
| Compressor | $2,500 – $4,000+ ( depending on other variables, sometimes equipment replacement is smarter ask for a repair vs. replace comparison) |
Need Help from a Local Pro in Phoenix?
Magic Touch Mechanical is an award-winning air conditioning company serving Mesa, Phoenix, Chandler, Tempe, Gilbert, and nearby cities for more than 20 years.
Whether you need a repair, a second opinion, or are considering a new AC installation, we’re here 7 days a week—and we don’t charge extra for weekends.
📞 CALL NOW
💻 BOOK ONLINE NOW …
