Introduction: How to Rejuvenate a Box Fan

Picture of How to Rejuvenate a Box Fan

Many people throw fairly new box fans out well before their time. Like most small appliances, people don't take the time to clean them, even though it will make them last much longer. I guess it is easier to put it out for the trash and spend another $20-$30. Whenever I see the towers of box fans for sale, I always wonder what happened to the ones people bought the year before.

After only one season a fan may be covered in enough gunk to give the illusion that the 'motor' is worn out, when really all that is needed is a good cleaning to keep it running for a lot more hours. I have often picked these up on trash day, and gotten years of use from them. Rarely I may have to replace a knob, but usually they are functioning, but the blade speed is about half of normal.

Step 1: Tools

Picture of Tools

Just a few tools, though you can use many more for cleaning depending on the gunk level.

Screw driver
Paper towel
Dusting Brush
All Purpose Cleaner/degreaser
Finger Nail Brush
green kitchen scrubbies
steel wool

Step 2: Remove Front and Back Grills

Picture of Remove Front and Back Grills

These screws are usually very small. put them in your pocket or somewhere SAFE.
Sometimes a few can be missing OR the hole has grown too large to reseat tightly.

Yes, you can skip a few, usually you can leave off a side screw without TOO much noise factor.
but you NEED the top and bottom tightly screwed down of the vibration will make a hell of a racket.
scout around for replacements - you want short and fat threads.

Step 3: Remove Grill and Fit

Picture of Remove Grill and Fit

You may have to unhook the power cord collar and remove the feet.
if the feet are missing you will have to dummy a replacement, or just make sure the fan is propped up, like in a window. Vibration at high speeds will make the fan walk and possibly fall.

Step 4: Brush the Motor

Picture of Brush the Motor

Remove all the material surrounding the motor, avoid spraying it with any cleaners.
Use a brush to remove the hair and gunk.
also wipe the struts.

Step 5: Wash Blades

Picture of Wash Blades

Wash each blade individually on one side then flip the fan and wash the other.
I find that some blades resist degunking and a scrubbie pad is useful to remove the stuck on gunk.

If you leave it gunked and only remove the visual material, new stuff will quickly latch on and you will be just as bad off. You want to end up with smooth clean plastic blades, where things slide off.

Step 6: Clean Fan Grills

Picture of Clean Fan Grills

This is tedious and you will feel like cutting corners. If you have more than one fan to do, leave the 2nd until the next day. Use a brush for the solid matter. then spray with a degreaser/cleaner and then scrub with a nail brush or other firm bristle brush. Then wipe with paper towels.

The grids are NOT straight but beveled, and may appear clean if you look at them straight on, look at them from an angle and you will see they have four sides, you don't need it spotless, but get the area in front of the blades reasonable clean. You CAN do these in the shower, and use a long handled scrub brush, but you will still need to use paper towels to get in some crevasses.

Step 7: Reassemble the Fan.

Picture of Reassemble the Fan.

Wipe the whole thing down inside and out.
Reattach the grills, the feet and align the power cord collar.
Turn it on, if the fan was not old to begin with you will find a world of difference between the speed of the fan blades before and after the cleaning.

I do this every season to my own fans and these $20 box fans last a lot longer then the manufacturers want them too.


BenW202 made it! (author)2017-05-11

Now days the box may have a fuse in the power right the hot power slider!! To replace the 2.5A mini fuse(@ yr fav auto parts store) pls no power/plugin, using a tiny screwdriver push the slot open replace the door, pop fuse out using screwdriver under each silver end, push the new fuse into said pocket, close the fuse door, plugin, fresh air!!!

ScottP12 (author)2015-09-09

That's how to clean a fan - no rejuvenate.


SamanthaF60 (author)ScottP122017-04-20

Cleaning it DOES rejuvenate it

ThomasT97 (author)2016-06-27

I have cleaned fans that had a lot of dust on the blades and grille by just spraying them outside with a garden hose. No disassmbly, left the motor in. I let it dry several days in the sun outside before using. I was concerrned about water in the motor but no problems years later.

ChristainD (author)2016-06-26

I have a fan that the fuse blew on the plug how can i replace that

_vaannaa__ (author)2016-06-19

Does anybody know the customer service number for cool master box fan?

quiltslongarm (author)2015-09-08

I have a new fan that is very noisy. Is there any way to make it quieter?

Thank you!

Is your fan a small 8-inch desktop? Most of the time it is a result of lousy bearings with so much play that the shaft rattles. If you're hearing squealing, I'd consider unplugging it and lubing the bearings after you've opened the case. There are several very small coarse-thread screws from the back that hold the front to the back half. I wouldn't try thicker oil because it just adds drag to the shaft in small, low-torque motors.

wastubbs (author)quiltslongarm2015-09-09

Returning it to the store or manufacturer will make it a lot quieter.

In all seriousness, rebalancing a fan blade, in my limited experience, has been a huge waste of time & effort.

Fan noise usually comes from vibration. Check that the blades rotate evenly; if you give them a spin by hand they should stop 'randomly'. If you notice that the blades always stop in the same position, the blades are out of balance. Try to clean them, look for small breaks in the plastic, etc. You *can* counterweight them with small pieces of tape, but once they are out of balance its almost impossible to rebalance them. Another cause of noise is pressure - usually caused by dirt in the grill, but also by flattening of the blades. Look for evenness doing the spin test.

I will do that. thank you!

Gary Viveiros (author)2015-09-20

Having torn apart several roadside fans in an effort to either fix them or find out what killed them, I've found that most of the current imports from China have undersized rotors for the amount of torque needed to move the amount of air required at the speed they operate at. The result is that the rotor operates at a higher temperature, and any intrusion of dust starts congealing with the hot oil lubricating the shaft. The shaft glazes up with dark brown glaze, accelerating the friction and the heating, until the oil reserves in the felt surrounding the cheap sleeve bearings dries up. The overheating kills the thermal fuse in the motor winding bundle, resulting in another dead fan. The fan should take 10 seconds to wind down to a stop if it is a 15-inch fan. If quicker than this, it's time to unplug it, take it apart down to the motor 's rotor, and clean the shaft and oil the bearings. Remove the shaft glaze with 'wet' sandpaper of 600 grit by holding the sandpaper in a loose wrap around the shaft and rotating the shaft. I've been able to keep my cheap Aurora fan alive for years by catching the signs of slow startup or quick wind down, or squeaky bearings, and shutting down the fan until I've ripped it apart and cleaned and lubed it using regular 30-weight motor oil.

princess.kimbrough.9 (author)2015-09-12

I have been doing this for years. It's amazing how a little bit of cleaning will go a long way!

gdanas87 (author)2015-09-12

you can also take it outside, use a can of compressed air (or at best to save money, if available from a friend, an air compressor) and clean it much much better this way. You can use this method to clean ANYTHING (ie. desktop computers, laptops, keyboards, you name it... ) Just hold the moving parts (like the fan blades) so they won't spin too fast and cause damage. Also, if you decide to clean a laptop this way, find a way to seize the fan(s) temporarily while cleaningn (ie toothpick or paperclip), and don't blow the compressed air too close to the screen (if you decide to throw air at the screen do it while holding the nozzle at least 30 inches away from the screen) and remember ALWAYS remove the batteries.

rick.leasure (author)2015-09-10

yep. now, how to increase their effeciency?

PatriciaD18 (author)2015-09-09

Great job. I also do this but use Scrubbing Bubbles to clean the grates. No

scrubbing with those bubbles doing all the work for me. Just rinse and dry.

ziggybass (author)2015-09-09

Well this post is at least seven 7 years old. Now all the fans are usually made in China 98% plastic and the motors are heat sealed in plastic housings. Re lubunig the motor like in the old days with metal fans, well that was easy. However today:If they are screwed on, take off any external plastic outer layers, If the fan has a revolving screan that re directs the air that can often be removed by turning the large centre locking knob (it's often 2" wide) keep turniumng it counter clockwise until it comes off. This will help with regular cleaning and depending on how the fan motor is fitted, should enable you to get at one end of the fan motor easily.

Make sure you have a 'Non Cundictive? Spray can of WD40 or one of the electrical sprays. (Don't use PCB Cleaner) that generally is conductive and only meant to be used to clean electrical parts before making something on a 'Printed Circuit Board'

When buying you spray Any Hardware Store in the USA or somewhere like B&Q in the UK and on both continents Radio Shack or RS Componants as they are known in Europe will have a range of cleaners. Remember 'Non Conductive!! Try to find a can that had the tiny plastic tube adaptor that fits into the can spray head nozzle. This will allow you to put the liquid right where you want it.

Where To Spray?

If the motor is encased then just tipe the fan horizontal so the motor faces upwards. Spray a little right where the shaft comes out od the motor. (I'm assuming you cannot get the fan blades themselves off) if you can that's even better! Spin the shaft and spray some more and continuw to do this. ?over spray may drip so have some old news papers under your fan. Turn the fan over and spray the liquid into any crevise or joint in the motor housing/body. Just keep doing this till the liquid reapers out the other end of the motor. Turn the fan over a few times then let it drain for an hour. The motor should start to turn a lot easier. If not repeat the whole process again.

If your unable to access the bearings or see inside the motor thats as good as it will get. Put the whole thing back together, wipe dry all excess liquid. Plug it in and switch it on. You should see/hear an instant improvment. When you stop and unplug the your fan see if there is any where around the shaft (NOT ON THE MOTOR)! where you can use one or 2 drops of sewing machine oil. If you have a hair trimmer or Beard Trimmer in the house, the Oil for that will do just fine! I clean my fans this way every year!

Hope this helped. Hugs From Spain!

codongolev (author)2015-09-08

I've been able to put the grille of my fan in a tub of warm soapy water and just swirl it around a bit. it knocks pretty much all the stuff off

EisenF (author)codongolev2015-09-09

Beat me to it! Nearly verbatim what I was going to say. I'll add, you can refresh locked up motors with Locktite - just wipe it off any plastic it runs on, as it will draw in dust from nearby counties. :D

100444bd (author)EisenF2015-09-09

What type of Locktite do you use and what do you use it for? Locktite makes adhesives and lubricants.

bpark1000 (author)2015-09-09

You don't mention lubricating the motor bearings. 90% of fan failures are due to the bearings running dry. If you're lucky, the bearings will lock up and cause the previous owner to discard the fan before the bearings are damaged. If the bearings are re-lubed, and have not worn loose from running dry, they will last forever. Use 30 weight motor oil to re-lube. Some bearings are sealed and are difficult to get the new oil in. Best way to do it is to disassemble the motor.

Clean grilles by spraying them with cleaner, letting them set, and lying them on the ground outside and give them a blast with a hose.

RockeyDA made it! (author)2015-09-08

pics of the fan!

RockeyDA (author)2015-09-08

a bit diffrent that my metod... i found a box fan in the sumpster with a locked up motor... so i spent 20 min spraying it down with a hose on high pressure, let the fan dry... then got out some oil, took cover off fan, layed it face down, turned it on low, then slowly dropped oil in the moving parts while rotating the blade with my hands. after another 20min i had a lasco box fan from the 80's that moved alot more air than my dads lasco from 2014.

iceman46222 (author)2015-09-08

I have done this with box fan's for many years, the best one is I got on out of the trash cleaned it up and it's is still going in my garage after19 yrs.

HaroldW4 (author)2015-09-08

I use to do it like this, but it took so long ... Now I just spray it with all purpose vcleaner and a little dish soap ... and in the shower it goes ... I lay it flat side up and let it dry for 2-3 hours .... fast and easy !!! I use my fan all year round to circulate the air, I've just gone through the 4th summer and my fan is still running as strong as the first day,

JanisF (author)2015-09-08

If I can dismount the motor and the switch (I can on my newest fan) and take the blade off, I just take the rest of the parts to the manual car wash and pressure wash them with soapy water (and rinse). I suppose I'd rather spend my time hacking the thing than scrubbing; I can't imagine it actually saves time to do it that way, but it's more fun for me. It's doable for just the grates, though, too. I do have to keep my distance though so as not to break or mis-shape the plastic.

I am perpetually frustrated with my mom who neglects her stuff like this, gets really frustrated when it "breaks," and then lets it sit in her garage because "it might be fixable." It probably mostly is, but there's such a mountain of stuff like that I'd spend a year getting through it, and now the mountain is its own problem. Proper maintenance rocks, for so many reasons. Excellent post.

Karenauto (author)2015-09-08

I've done this! The BEST and easiest way to clean the grilles are to lay them in the top rack of your dishwasher, they come out spotless, no elbow grease needed!

sitearm (author)2015-09-08

First, kudos for a clear Instructable explaining how to keep a box fan working with a little bit of "elbow grease" and minimal costs. Second, kudos for (inadvertently, I would assume o_O) triggering one of those aMAzing humongous comment chains and sub-chains that veer all over the map - 139 (counting me) and rising : )

RiversP (author)2015-09-08

If you have access to an air compressor, you can blow your fans out every month or so and may never have to clean them. Just don't let the air get the blade turning too fast or the motor will come apart. Using the air to turn the blades backward will make the yuk come off quicker.

nature223 (author)2008-06-08

also pull the BLADE off,and liberally lube up the motor shaft..BOTH ends,the fan side seems to go dry first. that makes a huuuge difference,they seem to spin forever turned off after being lubed up.compared to the hard almost screech to a stop they did "dry" also they move alot more air when spun up not fighting friction

robprimeau (author)nature2232008-06-08

Thanks for this info to. What kind of lubricant would you use on the motor shaft? Also, when you pull the blades off, where on the motor are the proper places to lubricate? I'm interested in not starting a fire:)

Gonazar (author)robprimeau2008-06-09

Just use WD-40, i thought that stuff was pretty much all purpose...

tmasman (author)Gonazar2008-06-09

The problem with WD40 is it's a solvent, not a lubricant... It works well to clean things up & lubes things pretty good while it's "wet", but once it dries up, there's no more lube! You really should use an oil or grease for long lasting lube.

leebryuk (author)tmasman2008-06-09

Do we really need to start the whole WD-40 conversation again? This isn't a hi performance electric engine. Anything you do to it will be far better than what shape it came in. If WD40 is what you have on the shelf, then use it. It will not bring about the apocalypse, nor does it have anything to do with the rapture. Use what you have and don't sweat the small stuff.

kill-a-watt (author)leebryuk2010-05-31

3 in one oil would be a good choice

you could also get some Automatic Transmission Fluid or 30 weight motor oil and thin it down with some kerosene. Using ether straight (neat for UK readers) would not be the end of the world, it would only be not ideal.

Sewing machine oil

And BTW, WD-40 is a solvent mixed with a lubricant. It also worked a lot better as a diesel starting fluid back when it was pressurized in the can with butane.

Calorie (author)kill-a-watt2010-05-31

Yes, you are correct. You are absolutely correct. But

WD40 is not just a solvent. It is a solvent with a lubricant. The solvent helps pull the lubricant into the tight places. Once the solvent evaporates the lubricant is exactly where it needs to be.

In the States it is largely sold in pressurized cans. Actually, I can't remember when I last saw it in a consumer squeeze can. I've seen it in a gallon container though.

The following isn't particularly relevant, but...
I use to volunteer at a bike rehab clinic. We used a motorcycle chain lube on the bikes going out into the world. We knew that they would see additional time on the streets and were unlikely to be maintained.

There's some guy who does tutorials both on youtube and Instructables. He just trips daisies if you even mention WD40. They behave like it is fuming acid sprayed on your bike. To him you need the expensive chain lubes that you dutifully dot into every link. And you must use certain greases only in certain areas in a bike's headset, etc. It's a little intense.
And the moral of the story...

Use what you have, because you already have it.

dougstrickland (author)Calorie2015-09-08

Another interesting fact of WD40 - its conductive. When TV volume controls used to make that scratchy sound when you adjust them, a simple shot of WD40 fixes it instantly.

kill-a-watt (author)Calorie2010-06-05

I don't see why people don't use full chain guards on bikes anymore. That would keep the chain in great condition and only add 1 or 2 pounds two the whole bike. Seriously, with the "fixie" craze, its not even safe to have a guard free bike. I can't believe more fingers, pant legs or socks don't get chewed up in those things. I use ATF on my chain and change it frequently. I've got a un-hip 6 sprocket freewheel that takes the cheap ahd heavy duty chain that they sell at wal-mart for a few bucks.

Calorie (author)kill-a-watt2010-06-06

That is so true! Full chain guards are the best. I have one on a dutch style bike. I rode through rain and snow, ice, salt, grit...everything. I take it apart every so often and check for wear. After 1,200 verified miles it is still clean and new.

*The fixie stuff gets under my nerves as well. I want to strangle a person when they offer a lame beneift of "it's so much less maintenance." They aren't. Modern drive trains are incredibly reliable. I wish they would just admit it's for fashion. Then I would just think it was their choice.

*I agree with you once again. Ride what you got. And keep it cheap. My road bike is 6 years old, and will be fine for another decade. Mix it up and have a nice time. Buying something too expensive makes you nervous about damage and theft.

*For the oil I would honestly say that WD-40 works fine. If you want to step it up a notch use Gt 85  I've used it for years and it is available in your local bike store. But honestly, WD-40 is fine. Just don't tell the bike police!

*I do think that the bike mechanics have a point, but they are confusing correlation with causation. The bikes that have been lubbed with WD-40 come in an awful state. So they make a connection between trashed bikes and gunked chains. But I personally think it's really a situation of those who use WD-40 don't know how to maintain a bike.

Mark 42 (author)Calorie2015-09-08

My mountain bike is from the very early 1980's.
When I bought it, most people had never seen one.
It's a GT Timberline. I had never seen one either, and one look at it said to me :Now this is a bike that would be very functional - like an early Land Crusier (FJ-40) - useful for roads and trails.

I still ride it more than any other bike I have.

bgrothe (author)Calorie2015-09-08

I agree.

i have a 25 year old cannondale mtb and it is still going strong. I get new bearings every now and then and re-pack with automotive wheel grease it is thick it last a long time. my son just recently went to get bearings for a hub and he let the guy talk him into a little 3oz container of grease for $9.99. way over priced. For chains I keep mine clean and then just use a generic silicone lubricant. For the first 5 years of its life it was ridden approx. 25 to 30 miles of offroad use a week and another 50 to 75 miles of on road per week. In fact when ever he can my son will take my bike and ride it instead of his Specialized Rock hopper.

jopolitesse (author)Calorie2015-01-05

You are cool and smart! I second and double everything you say!! I've used WD-40 on a lot of "off-label" things over the past 25 years, and no harm has ever come of it.

Yard Sale Dale (author)Calorie2014-11-25

WD40 kills bike chains and bearings if used as a "lubricant".

rustaholic (author)kill-a-watt2012-10-28

3 in 1 oil also makes an oil just for electric motors.
I have also maintained larger electric motors at work that take 20WT non-detergent oil for their bearings,

john.moody.351 (author)leebryuk2015-01-09

Incorrect. It will actually disolve any factory applied grease. And it will dry out quckly. End of motor. Any industrial maintenence man will tell you that as well.

CobraSlammer. (author)leebryuk2014-10-26

I see this is 6 years old, but for the sake of preventing misinformation for whoever is reading- NEVER USE WD-40 ON ELECTRIC MOTORS!! WD-40 is made for breaking loose nuts and bolts and preventing rust. It will TEMPORARILY (like 5 minutes) free up an electric motor, after which it dries and DOES make it WORSE off than it was before. It'll dry out and burn up into a thick sticky gum. WD-40 is good for what its made for, which does not include lubricating ANY type of motor, no matter how high or low cost. There's oil made for electric motors and it isnt hard to find. Anyone who keeps saying WD-40 can be used on high speed moving parts obviously hasn't seen what happens when you do that.

SkippySue2022 (author)leebryuk2014-08-15

I'll be as nice as I can muster. Leebryuk, did your half-a$$ed opinion help ANY one? Now, why on Earth would you go through all the trouble of breathing new life into it if you're just going to use ether in the resuscitation bag? If you have a job to do, it's worth doing right the first time.

my_key (author)leebryuk2008-06-13

Why not. It learned me something I didn't knew :) I already suspected that the lubrication of WD-40 was pretty volatile, since I noticed that yesterday while trying to lube something. But thanks to you guys I know about the Water Displacement. Thanks. I'm a happy man now.

jgodsey (author)tmasman2008-06-09

Where's the love for Marvel Mystery Oil? always have a bit of that stuff around.

x7319808 (author)jgodsey2011-01-30

My dad used Marvel in his air tools to keep them lubed up.

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