What does a bad furnace fan motor sound like?

Author: Alfred Wilderman  |  Last update: Saturday, July 12, 2025

Over time, normal wear and tear can cause the furnace motor to start squealing, grinding, buzzing, or whistling sound. Here are some of the most common culprits behind furnace motor noise: Bearings wear out – Bearings allow the blower wheel to spin smoothly.

How can I tell if my furnace blower motor is bad?

Here are some signs of a broken furnace blower motor:
  1. Loud Operating Noises. When your blower has an issue, you might hear odd noises coming from your vents. ...
  2. Weak or Absent Airflow. Weak airflow or total lack of it is the most obvious sign of a bad blower motor. ...
  3. Overheating. ...
  4. High Energy Bills.

What does a bad blower motor sound like in a furnace?

If it's a metallic, whining, or banging noise it's a bad blower motor, in which case you should shut off the furnace and get repairs immediately. If it's a loud electrical hum, then it's a bad transformer. If it's a rumbling noise, then that's an issue with the burner, which can be extremely dangerous.

What does a bad fan motor sound like?

A sure sign of a bad fan motor is a cooling fan that will not come on. The cooling fan should spin continuously during operation. You may hear a slight buzzing sound from the fan, but the fan will not turn at all if the motor has failed.

What does it sound like when your blower motor is going out?

A failing blower motor may emit unusual sounds. This may sound like screeching or squealing if it has bad bearings. You may hear a rattle or a banging sound if something inside the motor has broken or come loose.

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How do I know if I need to replace my blower motor?

You should replace your blower motor when you notice the following signs:
  1. Weak Airflow. The first indication that you have a faulty blower motor is when the airflow out of your air conditioner is weak. ...
  2. No Airflow. ...
  3. Unusually High Energy Bills. ...
  4. Strange Sounds. ...
  5. Overheating.

What happens when your blower motor goes out on your furnace?

If the blower fails to operate, you won't receive any heated air through the vents in your home. If the blower isn't turning on at all, this is a symptom that can indicate a full replacement motor is necessary.

How do you diagnose a bad fan motor?

Be aware of the following signs and symptoms of a bad AC fan motor.
  1. AC Fan Doesn't Start. Even though you have the AC turned on, the fan does not start.
  2. AC Fan Doesn't Stop. ...
  3. Slow Rotating Blades. ...
  4. Outside Fan Blades Are Still. ...
  5. Rattling, Humming, and Buzzing Noises. ...
  6. AC Runs Intermittently. ...
  7. No Cold Airflow.

What is the life expectancy of a fan motor?

A blower motor should last at least 10 years, and could last up to 20, depending on the type of HVAC unit you have in your home. There are a few warning signs that your blower motor is damaged, including little-to-no airflow coming from your vents, a burning smell, and skyrocketing energy bills.

How do I lubricate my furnace blower bearings?

You'll probably have to remove an access plate to get at the ports. If the blower has grease cups instead of oil ports, remove the screw caps that cover the cups and fill the cups with bearing lubricant, which is available at automotive and hardware stores. When you lube the motor, you should also check the belts.

How much to replace a furnace blower motor?

Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.

Which of the following is a common symptom of faulty blower motor?

Strange Rattling, Clanking, or Screeching

One of the first signs you may notice when there's an issue with the blower motor is a strange noise coming from the indoor unit or air handler.

When should I worry about my furnace noise?

Loud Bangs, Rumbles, Knocks, or Booms

Loud noises like this are a sign of a build of gas in a furnace. The noise you hear can mean your heat exchanger is at risk of cracking. Even worse, it's a sign that something dangerous could happen if you continue to use your heater.

What is the life expectancy of a furnace blower motor?

Typically, the lifespan of furnace blower motors spans from a minimum of 10 years up to about 20 years, with most enduring an average period between 15 and 20 years. The same blower motor is used for both heating in the winter and cooling in the summer, making it essential for maintaining indoor climate control.

Should I replace the blower motor or buy a new furnace?

Replacing the blower motor is likely the best decision if your furnace is under warranty or relatively new. It might be better to replace the furnace if it's old or has a lot of issues that require frequent repairs. On average, a new blower motor costs $300 to $900.

How do I know if my furnace blower motor capacitor is bad?

Signs of a Bad Furnace Capacitor
  1. Symptom: Clicking Noise. Fortunately, a capacitor can show symptoms of failure before, or during a failure event. ...
  2. Symptom: Acrid Burning Smell Coming from the Furnace. ...
  3. Symptom: Humming Sound from the Blower. ...
  4. Symptom: No Power At All. ...
  5. Symptom: Erratic Motor Operation.

How do you know if your fan motor is going out?

Here are some signs you may need AC fan motor replacement.
  1. The AC Fan Won't Start. The most obvious sign that your AC fan motor is bad is when it fails to start the fan blades at all. ...
  2. Slow-Moving Blades. ...
  3. Loud Noises. ...
  4. Overheating. ...
  5. Short Cycling. ...
  6. Tripped Circuit Breaker.

How often should I clean my furnace blower?

How often should you clean your furnace blower? Generally, it's recommended to clean it at least once a year. However, if you notice signs of reduced airflow, unusual noises, or increased dust, more frequent cleaning may be necessary.

What is the life expectancy of a furnace?

What is the average life of a residential furnace? A furnace that receives regular maintenance can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend the life of a furnace even longer.

How do you know if your fan motor is burnt out?

Some commonly occurring signs that you have a problem with your blower fan are that there is no air coming out of the registers even though the system is running, there is a loud rattling noise, and there is a burning-type smell within the system.

What can cause a fan motor to go bad?

Overheating. Overheating is one of the most frequent occurrences that can render the blower motor inoperative. If the motor has overheated, it may shut itself down to prevent damage. You should keep your HVAC clean and clear of any blockages or debris to avoid overheating and maintain efficiency.

How to tell if a furnace blower motor needs to be replaced?

Here are the key indicators:
  1. Unusual Noises. Screeching or Squealing. ...
  2. Weak Airflow. Insufficient Heating. ...
  3. Motor Overheating. Excessive Heat from the Furnace. ...
  4. Inconsistent Performance. Start-Stop Issues. ...
  5. High Energy Bills. An inefficient, struggling blower motor often increases energy usage and higher bills.
  6. Age and Wear.

Can a bad furnace blower motor cause a fire?

Your furnace will need to work harder, the blower motor will run for extended periods of time, and this could cause it to overheat. The devastating effect of internal temperatures climbing is that components could catch fire.

Where is the reset button on the furnace blower motor?

Typically, you'll find it inside the air handler, either next to or above your furnace. In most newer systems, the button is often directly next to the blower motor, while in older systems, it may be harder to spot as it is sometimes underneath or behind the motor.

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