Although very few vacuum cleaners can actually be considered quiet when they are being used, there are certain loud noises that if emanating from a vacuum usually indicate there is some sort of problem. In many cases, simply being able to identify the loud noise will give you a good idea of what the problem is and how to correct it.
1. Rattling Noises
A persistent rattling noise while the vacuum is running can be caused by something as trivial as a small stone having been sucked up into the beater brush area. If you suddenly hear a knocking or rattling noise coming from the beater brush area, don’t be too alarmed. Switch off the machine and the stone, or another small object, will probably fall out.
2. Whistling Noises
Whistling noises are often caused by air being blown across a narrow gap. A small split in the extension hose can give rise to whistling noise as can something like a large leaf or a piece of garment or material that gets stuck inside the hose. Some hoses have an aperture that can be opened to reduce the suction at the head of the hose. At times, these apertures can also give rise to whistling if you have your finger near one and inadvertently open it.
3. Grinding Noises
A constant grinding noise can come from either the fan or the motor while an intermittent grinding noise can come from the wheels of the vacuum. If the fan blades get damaged and have jagged edges, they will no longer cut through the air freely. The turbulence caused will shake the fan and make it sound as though it is being ground down. The turbulence will also interfere with the smooth flow of dirt and debris around the fan causing them to collide with the fan.
If the bearings on the electric motor have worn because of lack of grease, they will wear unevenly and grind against each other and the bearing rings. This sort of grinding is very serious, and the machine should not be used until the problem has been repaired. In extreme cases, damaged bearings may become very hot and melt the plastic housing. Often, the thermal cut out will not detect this heat until it is too late to prevent major damage.
Another grinding noise that is more obvious when the vacuum motor is spinning up or slowing down is caused by the fan becoming loose on the motor spindle. When the motor starts to turn, the inertia of the fan holds it in place for a few seconds until the added friction from the spindle causes it to start turning.
When the vacuum is stopped it is possible for the fan to continue rotating around the spindle for a few seconds. Although it is most unusual, an intermittent grinding noise can be caused when a bearing on one of the wheels breaks down. Large canister cleaners sometimes have this problem. This grinding noise can be loud, but will usually only occur when the vacuum is being moved across the floor.