Synchronous Motor - What's The Correct/Best Lubricant

No subforum seemed more appropriate than any other, so I’ll post this here.

I’d like to ask anyone who’d know (electronics or small engine/motor engineer/mechanic, experienced small electronics repair, or just someone who happens to know) what the proper type of lubricant would be for re-lubricating the gears of the small synchronous motors that do the oscillating function in most ‘modern’ oscillating fans.

It seems this is the part that is designed to fail in 3-6 months (and/or cannot handle being on near or at 24/7).
I’ve taken several apart and cleaned them all out, and re-applied lubricant of several types and nothing seems to work well.

I’ve tried an oil, silicon paste/lube (used for brake caliper slide pins, and other stuff), a thicker - more heavy duty brake parts “lube”/almost like a grease. They all failed. The motor runs well and silent after the cleaning and re-lubing, but quickly starts making noise and the oscillation starts stuttering.
The lubes all burn up or turn black. The motors get pretty hot.
It needs to be high temp and pretty thick I’d think.

Whatever they use from the factory seems to actually dry out. But I’ll often notice that brand new oscillating fans will have an oily liquid running down from the motor area soon after they first used, sometimes it’s from the motor.
One manufacturer said they use “vegetable butter”… what the fuck?

I know I can replace the motors, but they’ll probably suffer the same fate from the poor lubrication, and I like to fix things - and improve on them where I can.

Thanks for any suggestions. Not including “get a new fan”. The fan(s) themselves are great.


I use some reel grease made for fishing reels. For the motors a couple drops of 3-in-1 oil gets another 6 months out of them when the bushings get dried out and the motors start to seize up. A squirt of WD-40 first to loosen things up then run for a bit to evaporate the solvents in it then two drops of the 3-in-1.

These cheapo chinese fans are only good for about a year even with lubrication but so cheap it’s not too painful to keep a couple spares on hand.

If the fan can be placed out of the way I leave the cage off the blades so there’s less weight and stress on the oscillating mechanism or just leave the back one on. You can stick your finger in the blade of a running fan and it doesn’t cut you. The outer edge of the blades will if you run your head into from the side. Ask me how I know that. lol

I just bought a new 16" wall mount fan that will come on to where it’s set when running off a timer. I have that one plugged into the timer that turns on my grow lights so it blows across the canopy. A 12" one is going 24/7 down lower to keep the air well mixed up in the grow room. When I see those on sale I’ll buy 2 or 3.

Last year I bought a 16" wall mount with a remote control but if the power to it goes off you have to either use the remote or the buttons on the fan to turn it on again. So no good to use off the timer. I was right pissed off but it found a life mounted up on the wall in my mancave and I’m loving the remote now.



Hey, thanks for the reply.

Are you talking about this kinda motor though?
It’s not the motor that spins the fan blade, it’s only responsible for the oscillation.

WD-40 is more of a cleaner; it’s not a “lubricant”. Reel oil is too light. 3-in-1 is good for the actual fan bearings shaft, but not the gears in the synchronous motor (too light again I think).

The fans themselves are excellent, that’s why I’m even bothering doing this, hah. The only issue is these piece of shit synchronous motors.

Even if I could find a better made one (USA, Taiwan(?), Japanese(?) made maybe) that I knew was quality, I’d pay for that.
The only thing I think I came across that might’ve been better made were for microwave turntables and had different terminations (which I could surely work around…but I might be a bit annoying).


Plastic or metal gears?

I’d tend to go for some silicone lubes (we use silglyde) maybe a dialectric grease?

Since they are probably plastic, have you checked for wear on the gears them self? If they’re worn or chunky no grease will help you.


How about that thin silicone grease they use for taps and valves in fresh water systems?
Or maybe some spray grease?

I went through loads of fans over the years, most don’t stand constant use very long. Small grows are easy though, you can string up a bunch of 5" PC case fans fitted with home made guards, plant wire works well for that. They are nearly silent and can last years with no maintenance at all. Connect them to a variable voltage power adapter (max 12v) then you can even vary the speed :+1:


pneumatic tool oil


I’m talking about the regular gearbox oscillating type fans that are driven by the motor that spins the blades using a worm gear setup. Not reel oil but reel grease. Comes in a tube and is about the consistency of Vaseline.

The WD-40 is just to dissolve the gum that builds up in the fan motor sintered bronze bushings. Ill spray some in there then run the motor for a while to loosen everything up and dry off the solvents then put in 3-in1 oil for lubrication. 3-in-1 also makes an electric motor version as well.

You sound like you’re building your own fan.



Ok, for a quick reference and great information source, McMaster Carr is great.

So, that out of the way, I use wheel bearing and chassis lube :laughing: :sweat_smile: :star_struck:
The stuff has great specs.
I did a tear down on my 12" tent fan before this grow. It had a couple hard years on it and was doing that move hesitate move thing. Well it wasn’t designed to be opened but that hardly slowed me. The grease the factory used was…ok… and it was sort of where it should be. It was open so I cleaned and reapplied. Didn’t fix the movement but I know it should be good for a couple more years.



Good tip. Just repaired my hurricane wall fan. The motor housing cracked on one screw allowing it to slip enough it stopped oscillating. Swapped it for the spare and did a full plastic weld splint. Shouldn’t break on that screw now but I am sure it will need more work in a couple months.
Never be scared to tear apart something that’s broken. What’s the worst that can happen. You learn something.


I’m the guy in the background smoking, acting like I know what’s going on.


try vegetable oil i think that what they mean when they say vegetable butter.


I’ve been applying that theory since I was 7 :laughing: :sweat_smile: :rofl: :+1: :sunglasses:

Plastic parts and metal fasteners… Always a love/hate relationship.
There are a couple variables in there that cause most of the problems. Over torquing screws is the biggest and the easiest to do. Might not crack today, maybe 6 months but eventually the plastic succumbs to the stress.
My trick is to just snug it down and resist that urge to give it another 1/4 turn. Or if you did give that 1/4 turn, back it off slightly.



It took me years to learn this lesson!! When I was younger I over torqued everything, didn’t want it to come loose!!


White Lithium marine grade grease.


Thanks everyone for the suggestions. I have tried: 3M silicon paste (dielectric grease), Reel oil, Superlube with PTFE, and some brake lube/anti-squeal (purple stuff). Almost all failed in some way or another. I’ve ordered a (mostly) metal geared motor to try, but still, I think the lubricant is key. These motor get hot, 40-50C in parts…

The gears are mostly plastic. The smallest, on the shaft of the rotor (magnet) is plastic, the next is plastic with a reduced gear that’s metal, which turns a plastic gear with another metal reduced gear, which turns the final gear that turns the actual armature and is all metal.

Yes, actually the first one I inspected had a broken tooth on one of the plastic gears. I didn’t try and repair/use that. I think there was some minor chewed up’ness on some teeth of some gears too, of the motors that went to long without…help.

Hmm, not sure about that. But I’m not sure a thin lube will last. And the small PC case fans won’t do in this scenario.

Interesting, I’ll check this out.

Ahh - yea, wrong type of fan entirely, a separate motor oscillates this.

Oh, reel grease, ok. I’ll have a look.

That’s right, you did say the WD-40 was just to un-gum that buildup. But again, you’re talking about a different motor/part of the fan altogether I think. I completely disassembled the actual fan (blade) motor as well, and cleaned/lubed it. I think you’re talking about squirting stuff at/on it (a different fan part) without any disassembly, to get it going…no? Which is fine.

Haha. Nah, just trying to find the best lubricant for a synchronous motor. And/Or a good replacement motor that has higher quality parts etc.

That’s the mindset I’m looking for, hah. Ok, I might give that stuff a try. Thanks for the suggestion. You’re talking about a 12" oscillating fan?

Nice one, man. Good job, and I agree.

Ok, I think they call it that if it’s not animal byproduct. (And ps: I wanna use something better than whatever they’re using, because whatever they use melts off in 12 hours of use of a new fan. Haha).

Thanks for the suggestion. I looked into lithium vs silicon and can’t remember right now what I got from that… haha.

Edit: spelling.


Ya like the garage guys that impact lug nuts for an extra 30 seconds on each. I only use a torque wrench on mine and they come off as easy as they go on.


if whole motor is getting hot check the amount of electricty going to it check to make sure it is wired up correctly for the amount of electric you or trying to run it on. the people who made the motor can make mistakes hooking the wires up or mot making a good connection.

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I’d use molydisulfide dry film lube. Slicker than owl shit and since it’s dry won’t attract any grit to bind things up