Your swamp cooler is making noise? In this article, we’re going to cover the most common noise types, including humming, screeching, buzzing, and more.
For each noise, you’re going to learn where it comes from and how you can fix it.
Quick answer: Swamp coolers often make humming, gurgling and crackling noises. These are expected. You can reduce these normal noises with anti-vibration pads. Screeching, buzzing, scratching and banging noises are signs of unlubricated parts, loose parts, or faulty electronics. You can fix these noises with silicone lubricant, by tightening the parts in place, or by replacing the noisy parts.
Summary: Swamp cooler noise causes & fixes
First, let’s have a look at the different noise types and whether they are dangerous or not.
|Noise type||Cause||Is it dangerous?|
|Humming||Loose installation, fan blowing, electronics||no|
|Screetching||Issue in power electronics||yes|
|Buzzing noise||Stuck or clogged fan, issue in power electronics||yes|
|Gurgling noise||Air in water distribution lines||no|
|Crackling noise||Parts expanding or contracting due to temperature change||no|
|Scratching noise||Fan bearings broken||yes|
|Banging noise||Fan or motor broken||yes|
7 Swamp Cooler Noises and how to fix them
Noise is always a sign of vibration. And vibration, in turn, is always caused by moving parts in a system.
A swamp cooler has many parts where things move. The most obvious is the built-in fan. The fan is either standalone (with a built-in electromagnetic motor), or in larger evaporative coolers, the fan and motor engine are separate components, connected by a V-belt.
Many swamp coolers also have a built-in pump, which can create noise.
But there are even more possible noise sources. Let’s have a look at all the noises and their causes in more detail!
1. Humming noise
A low-frequency humming noise is one of the most-common noise types in swamp coolers.
First off, many electric devices hum, since the electricity powering them is a low-frequency 50-60Hz alternating current.
So, if electricity causes noise, then it is likely a humming (unless there is a frequency transformation somewhere in the electronics, which is very unlikely).
The fan and the motor also operate at low speeds. Actually, a swamp cooler fan rotates quickly and blows a lot of air. But high fan speeds still result in low-frequency humming.
Imagine the fan in your swamp cooler rotates 1,000 times per minute. Sounds fast, right? Some strong fans even get up to 2,000 rounds per minute (RPM).
But in terms of frequency, that’s only
1,000 RPM ÷ 60 s/m (seconds per minute) = 16.67Hz
2,000 RPM ÷ 60 s/m (seconds per minute) = 33.33Hz
So, even very fast fans produce very low-frequency humming noises.
The floor your swamp cooler stands on carries this low-frequency humming noise through the walls and possibly even amplifies it (if it is close to the resonant frequency of your walls).
The pump could, theoretically, also be a source of the humming noise. But usually, the pump only runs occasionally to refill the water pads. So, it won’t produce continuous humming.
How to test
You can test where the noise comes from by answering the following questions:
Is the humming noise continuous? If yes, then it is likely your fan (or the fan motor). Else, the noise comes from your pump. Check if water sounds occur in combination with the humming noise.
You can double-check it by lowering the fan settings. If the humming decreases with decreasing fan settings, then the issue is for sure the fan.
If the humming is constant, regardless of the fan setting, the issue could be in the electronics, which respond to AC current with humming.
How to fix
You can’t really fix the humming in your swamp cooler pump unless you know very well what you’re doing. And you likely need special tools to open the pump and troubleshoot it.
There are two ways to resolve a humming pump:
The first solution is to replace the pump. Get an equivalent swamp cooler pump online, disassemble your swamp cooler, install the new pump and see if that helps.
The other solution (which I recommend) is to just accept your humming pump. You won’t find a pump that is absolutely silent. Although… when I think about it… if you really want a silent pump, you might be able to install a gaming PC water pump in your swamp cooler. These are of higher quality and designed for silence.
A humming pump is not dangerous. It is a mere inconvenience.
If the fan in your swamp cooler causes a continuous humming, your best bet is to simply place it on anti-vibration pads. I recommend these anti-vibration pads (click here to view them on amazon). They are designed for washing machines. But they work just as well for swamp coolers (which are a lot quieter than washing machines).
Theoretically, you could also replace the fan in your swamp cooler. But fans usually produce little noise as long as they are intact.
The key cause for swamp cooler humming is the amplification of small vibrations in the fan through the floor and walls. You can only fix this using anti-vibration pads.
Lastly, if you found your swamp cooler hums because of an electronic component, then I recommend the following:
Disconnect your swamp cooler from the power supply. Open its case and disassemble it until you see the electronic circuitry. Visually inspect the circuit boards and see if you find any blown or broken parts.
If you find something, replace it with an equivalent part. You can get them online or in a hardware store.
Else, if you don’t see any obvious issues in the electronic circuitry, you probably have to accept the humming as it is.
Technically, you can troubleshoot this until you find the issue, but the cause of humming is usually slight tolerance deviations in the electronics. Unless you have manufacturer-level knowledge, you are out of options.
2. Screeching noise
Screeching noises are very similar to humming noises. Usually, they are louder and higher pitched.
One frequent source of screeching is when unlubricated metal parts rub against each other. The metal parts excite vibrations in each other. And because metal parts are usually solid and have a high density, their resonance frequency is very high, which, in turn, causes the screeching sound.
Lubrication almost cuts out all of the friction and, therefore, eliminates the screeching sound.
Oftentimes screeching sounds also occur when you don’t use your device for a longer time due to corrosion. During this time, parts corrode. When you first turn on your device again, it screeches until the corrosion wears off.
One everyday example I encounter frequently is when I ride my bike. Especially when my last ride was in wet weather. When I jump on my bicycle and hit the brakes for the first time, they screech extremely loudly! Almost as loud as a car honk!
But after breaking for about 15 seconds on a downhill track, the screeching stops because the corrosion wore off.
It’s similar in swamp coolers. Especially since swamp coolers are always wet. They are always subject to corrosion.
A third possible cause of swamp cooler screeching can be broken power electronics. Especially when parts in close proximity to a capacitor or an inductance break, capacitors and inductors start screeching when they are subject to higher AC voltages.
How to test
You can test the cause of your screeching noise without opening the swamp cooler (at first).
The first step is to run your swamp cooler and wait for a few minutes. Does the screeching noise wear off?
If the screeching noise gets quieter with time, the cause of the noise is corrosion. Likely, you did not use your swamp cooler for a long time. Or parts in your swamp cooler corroded because of the humidity inside it.
In this case, you don’t have to do anything. The corrosion will wear off with increasing running time. Just be patient. You should hear significant improvements within an hour of running.
If the screeching noise does not wear off over time, you the issue is either (metal) parts rubbing against each other, or an issue in the power electronics.
To test this, you have to open your swamp cooler until you see the fan, pump and the electronic circuitry. Then, run it (with an open case) and hear where the noise comes from.
How to fix
When your swamp cooler screeches due to corrosion, you can just keep your swamp cooler running and wait for the corrosion to wear off.
However, to prevent future corrosion, I recommend adding lubricant. Usually, you can’t go wrong with this WD-40 silicone lubricant (click here to view it on amazon).
You can use that same lubricant if the screeching noise is due to unlubricated parts which produce a continuous screeching sound.
Parts you should lubricate are:
- Motor (if there is a separate motor in your cooler)
WD-40 lubricant solves most screeching issues.
However, when the screeching comes from your electronic circuitry, you have to find out which part screeches. Usually, capacitors or inductances screech when they (or parts nearby) are broken.
The reason is that capacitors and inductances build up alternating electric fields, which causes them to vibrate (and screech) when you apply too high AC voltage to them.
To replace broken electronics, unsolder any broken or blown electronic parts you find on the circuit board. This will require some soldering skills.
With new parts in place, try running your swamp cooler again. If everything went fine, there should be no screeching.
3. Buzzing noise
Buzzing noise in swamp coolers usually comes from either a broken part in the electronic circuitry, water on the circuitry, or from the pump.
When water accumulates on the electronic circuitry, even if it’s just droplets, it can create connections between parts where there should be none.
Likely, water in a swamp cooler won’t short-circuit anything, because tap water is used for swamp coolers and the water vapor inside swamp coolers does not contain many ions (salt). So, it’s not a good conductor.
A distilled water droplet between two electronic components is much like an added resistor between these connections.
It likely won’t break anything quickly. But it can alternate the workings of the electronics, which often results in a buzzing sound (if the power conversion component is affected).
Pumps oftentimes also make a buzzing sound. Especially smaller electric pumps. In this case, the noise is normal.
How to test
To check the source of the buzzing, open your swamp cooler and listen to where the buzzing comes from.
Usually, you can easily distinguish between buzzing sounds coming from the electronics and those coming from the pump.
Pumps oftentimes vibrate. So, you can also touch the pump and feel the buzzing noise. This helps with the location of the noise source.
Sometimes, when you touch the pump, the buzzing sound changes. Because, essentially, your fingers add dampening to the pump, which can change the resonant frequency and the amplitude of the noise.
( Don’t touch the electronics! You will feel an electric shock otherwise )
How to fix
To fix the buzzing noise coming from the electronics, disassemble your swamp cooler and take out any electronic circuit boards you find.
Dry the circuitry (if you find it’s wet). You can use a dry towel for this. And you can also place the electronics outdoors for drying for a few minutes. Swamp cooler electronics are not sensitive, so there’s no problem in doing that.
Also, inspect the circuit board for any burn marks and broken parts. Usually, you can see faults with bare eyes.
If you find an issue, replace the electronic component with an equivalent one that you get in a hardware store or online.
You can’t really fix the buzzing noise in a pump. Most small water pumps just buzz. Theoretically, you have two options.
- Replace the water pump: Get a better water pump online and install it. I recommend this Dial Manufacturing standard pump for swamp coolers (click here to view it on amazon)
- Don’t use the pump. You can remove it from your swamp cooler and refill the water pads manually.
This can, however, be annoying with time. But it guarantees absolute silence!
4. Gurgling noise
A Gurgling noise in a swamp cooler can only have one possible cause: Air trapped in the water distribution lines.
Now, that is absolutely nothing to worry about and technically not dangerous. The gurgling noise is merely an inconvenience.
So, you don’t have to fix this issue. But, of course, you can.
Usually, you will find gurgling noises in the water lines leading to the water pads. But it can also come from the water line that connects the tap (or water bucket) with your water pump.
How to test
Open your swamp cooler.
Turn it on and listen to where the gurgling sounds come from. If the water hoses you use are transparent, you might even be able to see the air bubbles trapped in the water lines.
How to fix
The simplest way to fix gurgling water distribution lines in a swamp cooler is to unmount the water lines, drain them, and reinstall them.
Alternatively, you might be able to hold the water line upright (so that the air bubbles rise up and leave the hose).
I prefer the first method since I fix a lot of computer problems with the same philosophy. Just do a full restart, and most problems are gone.
The reinstallation of the water lines is like a full reset.
To prevent trapped air in your water distribution lines in the future, make sure to connect the water line and pump tightly.
5. Crackling noise
Crackling noises are very common in air conditioning and heating devices. All devices which somehow affect a room’s temperature occasionally crackle.
The reason is that due to the temperature change in the swamp cooler, some parts contract. This causes them to rub against other parts, or even do micro-jumps when tiny tensions are released.
The crackling noise is completely normal and expected.
It does not only occur when the device cools down, but also when it heats up again after you turn it off.
The turn-on and turn-off phases are the time periods of the greatest temperature change. So, during these times, swamp coolers tend to create the most crackling sounds.
If your swamp cooler crackles continuously for a long time, then the issue might be a part overheating in the electronics. Then, you get a crackling sound that’s similar to a small fire burning.
How to test
Turn on or off your swamp cooler and listen for a few minutes whether it crackles.
If the crackling reduces after some time, after turning it on, then everything is good.
However, if you get a continuous crackling sound, check the electronics and see whether any parts look blown or whether smoke comes out anywhere.
If that’s not the case, then your crackling is likely safe.
It could also be air bubbles in the water pads popping due to the evaporation.
How to fix
You don’t have to fix a crackling noise in your evaporative cooler unless it’s a continuous crackling coming from the electronic circuitry.
In this case, look for the broken component and replace it with an equivalent replacement part.
Then, try to run your evaporative cooler again. If the crackling persists, then the issue might be another broken electronic part nearby.
Double-check whether you overlooked an issue on the circuitry.
6. Scratching noise
A swamp cooler that makes a scratching noise won’t run for a long time before it breaks down.
The typical scratching sound is caused by destructive friction. With destructive friction, I do not mean the expected kind of friction that wears down parts over long periods of time.
Destructive friction wears down parts within hours or even minutes of usage.
Only the moving parts in a swamp cooler can create a scratching noise, such as the pump, the motor, or the fan.
Usually, a moving part creates a scratching noise when bearings are broken or some screws holding something in place are loose.
Scratching is always a sign that two parts rub against each other, which should not rub against each other.
In large swamp coolers (such as a roof swamp cooler, or a larger non-portable device), the motor powers the fan via a V-belt.
V-belts wear down over time. When a V-belt breaks, or during the time before it breaks, it can cause scratching sounds, because rubber strands separate from the main V-belt body and rub against other parts in your swamp cooler.
How to test
Open your swamp cooler. Run it for a few seconds. You should be able to tell quickly where the scratching noise comes from.
In some cases, when parts are loose, you also see them shaking around.
And when the V belt is broken, you usually can usually see it wobbling around with loose rubber strands.
How to fix
If the scratching noise comes from a loose fan, motor, or pump, you can try fastening the screws.
Scratching noise, however, usually indicates a more significant fault in a swamp cooler.
For example, loose screws and broken bearings indicate a quality control issue. V-belts can wear down with time, but they should definitely last at least 10 years.
So, any swamp cooler that’s younger than 10 years should not have these kinds of failures at all.
Loose parts don’t loosen on their own. Vibrations usually cause screws to unscrew themselves over the course of months. Even when you tighten the screws again, it’s just a matter of time until they loosen themselves and the scratching noise starts over.
Most of the time, you are better off buying a new AC unit.
( I recommend a good one further down below )
7. Banging noise
When parts hit other parts with high impulse, it creates a banging noise.
Banging noise is the worst kind of noise you can find in a swamp cooler. But banging sounds are very rare in a swamp cooler.
Swamp coolers are very simple devices. So, there’s not much that can bang around.
A banging noise would indicate that the fan loosened itself and jumps around inside the swamp cooler.
Or, alternatively, something fell into the fan’s rotor and is now thrown around.
A banging noise can happen once, or it can be a continuously recurring banging.
Both cases indicate the same kind of problem: One loose part throws itself or another part around inside the swamp cooler. A continuous banging occurs when two parts stick (or somehow interlink) with each other and one part throws the other around.
How to test
You can open your swamp cooler and see where the banging noise comes from. But be careful. It could be that the part that causes the banging flings at you.
How to fix
I recommend getting a new swamp cooler. A banging noise is a sign of a complete breakdown.
And the part that caused the banging probably damaged other parts nearby as well.
In the worst case, it hit the power electronics. And in a poorly designed swamp cooler, the power electronics could, theoretically, put the water pads under voltage.
That’s unlikely but possible.
Anyways, no swamp cooler should ever make any sounds that go beyond humming or gurgling.
A banging noise is an absolute no-go. Stop using low-quality swamp coolers.
What if you can’t fix your swamp cooler noise?
Swamp coolers are quiet. If your swamp cooler makes annoying noises and you are not able to fix the issue with the ideas from this article, I recommend getting a new swamp cooler.
It’s more expensive than other evaporative coolers, but this one will work reliably for decades!
Of course, you will get a blowing sound with this one (since it got a strong fan). But this one won’t buzz, screech, or make scratching sounds!
It’s a one-off investment that will pay off for at least the next decade worth of summers!
You can fix most swamp cooler noise issues by checking that the fan rotates freely and lubricating all rotating parts.
If you have a larger noise issue, you can exchange the fan or the water pump.
Or when you are familiar with electronics, you can even fix broken electronics which cause buzzing sounds.
But as soon as your swamp cooler makes “break down”-sounds, such as scratching or banging noises, you should get rid of it and get a quality evaporative cooler instead.
Evaporative coolers don’t cost a fortune. So you should be able to replace yours if it does not work properly.
Swamp coolers are very simple devices. And due to their simplicity, there’s not much that can break down.
And if anything breaks down, it is usually a quality issue. So, just opt for a better cooler instead.
Also, you can take this as an opportunity to have a look at replacing your swamp cooler with an air conditioner.
ACs produce much more cold air than evaporative coolers. They don’t need to constantly as much air as swamp coolers to cool your room, so they are naturally quieter devices than swamp coolers. And, additionally, ACs can be portable as well!
Here’s a list of the quietest portable ACs!
( They don’t even cost more than a good swamp cooler )