There are many sounds made by vacuum cleaners.  Most are normal operating sounds, but with age and use machines will break, bend, or pick up something that creates a new sound.  This post is all about vacuum sounds and how to identify and diagnose what the sound is, where it’s coming from, and how to either fix it or remove the foreign object causing the sound.

To understand the sound a vacuum makes it’s first helpful to understand the mechanics behind the vacuum.  The sole purpose of a vacuum is to create an airflow.  That airflow must be of sufficient strength (measured in cubic feet per minute) so as to be able to suspend floor contaminants in an airflow and deposit them into a waste receptacle.

Depending on the style of vacuum, each vacuum will originate sound in a slightly different manner.  Most vacuum cleaners will originate the most sound from the power plant fan assembly.  This is where fan blades cut into ambient air pressure and forcefully push air in a single direction.  This process of pushing air creates a vacuum which is then filled by in-rushing air from the front of the machine.

The fan blades generate the majority of the vacuum cleaners sound from the air that is collapsing together after the fan blade cuts through it.  Your vacuum cleaner shares the same physics as a helicopter.  The thump thump thump heard from a helicopter flying is the air collapsing back together as the rotor cuts through the air.

The fan assembly is rotating very fast and the impeller vanes are much smaller than the rotors of a helicopter.  So, the pitch of the sound from a vacuum is much higher.

Other sources of mechanical noise can come from a power plant cooling motor and fan.  When a power plant is sufficiently large it sometimes needs an additional fan to circulate air around the motor to keep it cool.  This fan can produce a high pitched whine as well.

If the vacuum is older, it may be suffering from dried out or dirty bearings.  There is a common shaft that goes between the power plant motor and the fan assembly.  To hold the shaft in place so there is minimal rattling, manufacturers place two bearings consisting of many ball bearings immersed in grease.  The motor shaft is inserted through both bearings and should spin with minimal friction.

occasionally, the protective dust cover to the bearing pack becomes damaged or dried out.  This allows sand and other dirt to become mixed with the grease in the bearing pack.  Over time the sand grinds against the bearings and will deform them.  This would also cause a louder motor noise when the motor is spinning.

Manufacturers try to design power plant enclosures that are free from loose or potentially loose parts.  If your vacuum machine is handled in a rough manner, it is possible that a wire or some other internal part has inched its’ way towards the fan assembly and is now being rubbed by one of the moving parts of the power plant or fan assembly.

The rubbing sound, depending on what is rubbing, may make a loud noise or just be a constant hum.  The pitch will not change as it remains constant due to the speed of the motor.

Occasionally a vacuum will pick up an object like a screw, coin, marble, etc.  It may be too large to successfully traverse through the fan assembly impeller and just rattle around in the intake area of the impeller.  If your machine has a metal impeller there is little to worry about.  Just open the machine and shake out the offending object.  If, however, your machine has a polymer impeller (plastic) then this needs to be addressed as soon as possible before the impeller is damaged.

During the fall months this is more of a problem.  Sucking in leaves or other objects like paper and plastics can sometimes cause a blockage where the object becomes lodged is such a manner as to cause it to flutter in the airflow of the machine.  This is a very distinct sound unlike the sounds from the power plant and bearings.

To solve this, one needs to take a peek through the different attachments connected to the vacuum cleaner.  Experience with your machine will tell you where the obstruction is most likely located.  Start with where the obstruction entered the airflow and work back towards the power plant.  To remove it, and depending on where it is, one will need to be creative.  Often a hanger can be of great help

there is no better place to find obstructions than in the power head of a vacuum attachment.  The power head has its’ own motor, bearings, and power belt that are independent from the other moving parts of the vacuum cleaner.  Many of these power heads will pick up coins and spin them around making quite a racket.

Depending on your machine, it may be an easy task of removing foreign objects, or it may be a project to dis-assemble the different guides, roller, brushes, et. al.  While its dis-assembled find a pair of scissors and cut all that other stuff on the rollers off.

The power head uses a belt to drive a beater bar or brush roller.  The beater bar does just what the name implies.  It beats the carpet as it spins to dislodge floor contaminants and move them into the machine airway for removal.  Sometimes a beater roller can be quite loud, particularly when it is bouncing on a more solid surface.

there is no better place to find obstructions than in the power head of a vacuum attachment.  The power head has its’ own motor, bearings, and power belt that are independent from the other moving parts of the vacuum cleaner.  Many of these power heads will pick up coins and spin them around making quite a racket.

Depending on your machine, it may be an easy task of removing foreign objects, or it may be a project to dis-assemble the different guides, roller, brushes, et. al.  While its dis-assembled find a pair of scissors and cut all that other stuff on the rollers off.

The power head uses a belt to drive a beater bar or brush roller.  The beater bar does just what the name implies.  It beats the carpet as it spins to dislodge floor contaminants and move them into the machine airway for removal.  Sometimes a beater roller can be quite loud, particularly when it is bouncing on a more solid surface.

There is nothing easy about clearing a hose blockage that is causing noise or stopping other material from passing through.  A coat hanger is still the best solution followed by a clump of fabric tied to a string.  The coat hanger can knock things loose, but the clump of fabric and string is better at pulling objects through.  Use the string as a pull and the clump of fabric as the plug to clean the inside of the hose.

Think of Mary Poppins and Dick Van Dyke in the musical number Chim Chim Chiree as you tug your hose sweep through the hose; just like a chimney sweep does to a chimney.

Whistling noises are almost always airway noises.  Either an attachment is not affixed tightly or there is a break in a hose somewhere.  Either way air is seeping through a hole and whistling as it does so.

Sometimes a whistle can come from an object that is scraping against a housing either in the power head, impeller, fan, or motor.  This is a bit unusual, but it does happen.  Some attachment just make whistle noises because they are restricting the machine airflow during use.  Sorry, no solution here other than hurry and get the vacuuming done.

This is definitely a cause for concern.  If you hear a grinding noise or a new whistling noise along with an odd odor, you should shut down the vacuum right away.  The machine may have picked up something it shouldn’t have.  Or, the machine has lost a bearing and the motor is rubbing against something it shouldn’t inside the vacuum cleaner.  Best not to create a fire or at least release acrid smoke into the house.

If you ever hear a whistling noise coming from the battery or a hissing noise take action immediately!  Remove the vacuum from the house and place it on the ground outside.  Hissing noise with an odor from the battery can be the prelude to an explosion or fire.  This symptom is indicative of a Lithium battery undergoing a rapid internal discharge.  Lithium is a relatively stable compound when cool, but when hot it can be explosive.

Not every vacuum cleaner is a screamer when operating.  Generally speaking, upright vacuum cleaners are much quieter than other styles.  This is due the power plant and fan assemble housing.  In an upright there is usually more machine surrounding the motor and impeller.  This added housing makes the machine much less noisy.

The noise that emanates from these larger upright machines it typically lower in frequency and more throaty.  Most people don’t find the machine noise disturbing in these styled machines.

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