Furnace Blower Motor Overheating – What To Do?

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When the weather is cold, the last thing that a homeowner needs is a furnace with a faulty blower motor. Often, if the blower motor is overheating, it can spell disaster for the furnace itself. But what causes this? And what do you do if your furnace blower motor is overheating? We have researched the answer to these questions, and this post will go over them.

If your furnace blower motor is overheating, the best thing to do is turn off the unit and check the air filter and vent ducts. A clogged air filter or vent could be causing the blower motor to overheat due to airflow restriction.

Try to replace the air filter to see if this fixes the issue. If not, turn off the unit or use it as little as possible and contact an HVAC technician as soon as possible. A blower motor that overheats is likely to fail at some point, which can be a huge inconvenience and a costly repair job.

There are signs that you can look for to determine if your furnace's blower motor is overheating. Sometimes the solution can be as simple and easy as replacing the air filter. And other times may require a complex repair or a blower motor replacement. Continue reading to learn about why blower motors may overheat and the signs to look for.

A furnace blower motor photographed in the basement, Furnace Blower Motor Overheating - What To Do?

Recognizing When Your Blower Motor Is Overheating

The blower motor in an HVAC system blows the heated air throughout all of the vents in your house. If this component fails, the furnace will no longer be operable.

So, it's a critical component within the furnace, and you should always address any potential issues with it immediately. Here are some signs that indicate the blower motor is overheating.

An up close photo of a furnace blower motor

There is a burning smell coming from the furnace

If you notice a burning smell coming from the furnace while you're troubleshooting it, chances are that the motor blower is working too hard. This smell can also come from the vents in your home or the exhaust pipe.

It may smell like burning oil or plastic. If you notice the smell, turn off the furnace immediately and check the air filter and vents for blockages.

The furnace is making strange noises

Strange noises coming from the furnace are one of the biggest tell-tale signs that the blower motor is overheating. If you hear any loud thumps or clanking sounds coming from the unit, chances are it's the blower motor.

These sounds can occur when the blower motor is experiencing an airflow restriction or if it is worn down from everyday wear and tear—as is typically the case with furnaces that are over 10 to 15 years old.

The furnace keeps shutting on and off

This is known as "short cycling" and is typically caused by a faulty blower motor or an electrical issue with the thermostat. Try resetting both the thermostat and the furnace to fix the issue. If this doesn't work, take a look at the air filter to make sure that it's clean and free of debris.

If it's not, change or clean it. If neither one of these solutions fix the issue, contact an HVAC technician.

Your home has hot and cold spots when the furnace is on

If you notice cold spots in your home while the furnace is running, the motor may be failing to vent correctly. This is often the case when the blower motor overheats, and it can spell disaster if it's not repaired or replaced immediately.

Many times this poor circulation is caused by vent blockages, dirty air filters, or blocked flue pipes. Be sure to check all of these areas if you experience cold spots in your home. If you aren't able to check the flue pipe yourself, it's best to contact either an experienced roofer or an HVAC technician to check it for you.

It's also a good idea to have the furnace inspected once a year, as a maintenance routine will include inspection of these components, which can help prevent this type of issue.

What causes a furnace blower motor to overheat?

Repairing a furnace motor blower

Unmaintained internal components

Scheduling annual maintenance is essential to keeping your furnace operating smoothly. When internal components (such as the coils) become clogged with dirt, soot, or debris, the heat exchanger can become overburdened. The blower motor is especially sensitive to dirt and dust, and if it becomes too dirty, it can easily overheat.

Electrical issues

Sometimes the electrical wiring in the blower fan can become worn out and faulty. If this happens, this can create additional stress for the blower motor, causing it to overheat and short-circuit due to inadequate circulation.

Restricted airflow

As mentioned previously, restricted airflow is one of the main reasons why a blower motor may overheat. Airflow can become restricted if the vents, flue pipe, or air filter becomes clogged.

When this happens, the furnace will begin to suck in air from the flue pipe, and the blower motor will overheat to compensate. This causes the motor to work harder than it normally would, which can quickly lead to burnout if the issue isn't rectified.

The furnace is old

And sometimes, the furnace is too old to continue to function correctly. And though blower motors are designed to last the entire lifetime of the furnace, they can go out prematurely. A blower motor can cost anywhere from $300 to over $600 to replace depending on its make and model.

This part is relatively expensive, and it's best to consider this if your furnace is over 10 to 15 years old. Sometimes replacing the entire furnace may be a better long-term decision.

Is a furnace blower motor supposed to get hot?

No. If your blower motor is hot, chances are that it is overheating. While this component does generate a small amount of heat, it is cooled by the blower fan.

What does a bad furnace blower motor sound like?

A damaged blower due to a circuit failure

A bad furnace blower motor can make a few sounds depending on the issue that it has. Here are a few common ones that you may hear if it's faulty:

Loud humming noises

Sometimes you can hear the sound coming from the vent, and other times you may notice it when you're in the room in which the furnace is located. Try resetting the furnace to see if it gets rid of the noise. Also, check the bottom of the furnace for any signs of breakage or damage.

It may also be a good idea to lubricate the motor to see if this stops the noise. If not, it's best to reach out to a professional.

Squealing or screeching sounds

Often, screeching or squealing sounds coming from the blower motor occur when the motor belt has become worn or when the bearings have become dry. Try replacing the belt and lubricating the bearings to see if this gets rid of the sound.

Loud thump during operation

Loud clanking or banging sounds coming from the furnace often indicate that a component has broken off or become loose from either the motor blower or its assembly. If you hear these sounds, turn off the furnace immediately and check the blower motor for obvious signs of damage.

It's also helpful to contact a licensed professional to inspect and repair or replace the broken part before operating the furnace again.

How much should it cost to replace a furnace blower motor?

The cost to replace a blower motor will depend on the make and model of your furnace. However, it can range anywhere from $300 to well over $600 for high-end furnaces. If your furnace is still under warranty, you may be able to pay as little as $100 for the labor.

Wrapping Things Up

A furnace blower motor photographed in the basement

If you suspect that your furnace is blower motor is overheating or otherwise faulty, it's best to have it inspected immediately.

However, before reaching out to a technician, it's also helpful to do a bit of troubleshooting to see if the issue is caused by restricted airflow from the air filter or vents, in which case, you can easily fix the issue.

And remember, before replacing the blower motor, be sure to take into account the current condition and age of your furnace. This will help you determine if purchasing a new unit may be more practical.

Before you go, be sure to check out our other posts:

What Does Furnace Service Typically Include?

How To Tell If Air Ducts Need Cleaning—10 Signs To Look For

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