Unusual and Loud Sounds 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.
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.
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.
You will hear the capacitor clicking every few seconds if it is bad. This noise is the capacitor trying to release the energy needed for the unit's motors to start. If the start capacitor fails, you will typically hear the motor make a loud humming noise.
A failing blower motor may emit unusual sounds. This may sound like screeching or squealing if it has bad bearings.
What's the Cost of Repairing or Replacing a Fan Motor? The average cost of a condenser fan motor is between $300 and $500 (not including installation). If the compressor breaks, you are looking at a much costlier problem which could cost up to $2000. In some cases, your fan motor may be under warranty.
Your AC is rendered useless without a functioning fan or furnace blower motor. This could also mean that you need a furnace repair or should start looking at costs for blower motor replacement. In addition, you will either suffer from no air or weak airflow with fan problems.
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.
A sure sign of a bad AC capacitor is a humming sound from within the access panel.
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.
Weak Airflow from the Vents
This is usually the first indication that you may have a faulty blower motor. If the airflow coming out of the vents is weak, check the motor. It can mean that your furnace blower motor is having a hard time pushing enough air through the ducts to achieve your desired temperature.
No Airflow from Vents
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.
On some platforms, a faulty blower motor relay will cause the blower not to work at all, which means there will be no airflow from the A/C. On others, the blower won't work on “high blow” but all the other speeds will work. The blower motor relay fails because it regularly deals with high current loads.
The short answer: Definitely not. (Unless you have manually engaged your outside fan to run constantly, but it shouldn't be running for hours on it's own.) If your HVAC is functioning correctly, it should keep your house cool by cycling on for 15-20 minutes at a time—with distinct pauses in between each cycle.
Unusual Fan Motor Noise. While a ceiling fan is designed to operate quietly, a faulty ceiling fan capacitor can cause the motor to emit unusual noises. If you hear a humming or buzzing sound when trying to start the fan, it's often the capacitor signalling distress.
If your engine is spewing fumes or has knocking sounds before ultimately dying out, then you definitely have a blown engine.