Recommended Oil for Small Fan Bushings?

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Jan 21, 2018
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Calgary, Canada
I have an Air King 9155 window fan that I have been using during the summer months for the past five years. The motor has spherical bushings, which are a bronze colour and might be sintered, but not sure about this. The motor also has three operating speeds and is 1/6 HP.

Several weeks ago the fan started making noises and had trouble starting on low speed. Eventually I took it apart, split open the motor and found a bunch of tar-like stuff in the NDE bushing which I believe was burned up oil. The bushing wick material was completely dry also. I cleaned it up and re-oiled with 3-In-One Motor Oil. Now it works fine on low and medium speed. But on high speed I hear a faint high pitched sound, like a metal-on-metal sound, and eventually after about 10 minutes of running it makes a loud squealing sound which I assume is coming from the NDE bushing.

I’m wondering how to fix this problem. I'm thinking perhaps the 3-In-One oil is too light and I should have used something heavier. What do you think? What is the proper oil for bushings on a small fan motor?
 
Spherical bushings for a rotating motor application? I don't think that's exactly ideal. Usually you'd use those for suspension components where you need a range of motion. A sealed ball bearing would be better.

Either way, it looks like 3-in-1 engine motor oil is listed as "SAE 20", I would try whatever xW-30 you may have laying around, and if that doesn't help, move to a grease.
 
you might have some excess play in the bushing now. if it is, i would pop the bushing out and replace it seeing you are adept at taking it apart. they are only a few dollar and can be had from grainger or the like.

this is how i fixed a portable air blower . the front bushing was so egged out that the cage was hitting the enclosure. $3 bushing and a hour or so and it works like new. they are $350 new
 
I have this fan, though mine has the Lasko label. It's a great fan.

I have helped fans with failing bearings by using the Tri-Flow lube that I use on bicycle chains. Does the PTFE help? I think so, in that it feels that I go longer between lubes, but I have no hard data.
 
If you can remove the bushing i think you can place them in a pot with hot oil and that helps them re absorb oil
 
Spherical bushings for a rotating motor application? I don't think that's exactly ideal. Usually you'd use those for suspension components where you need a range of motion. A sealed ball bearing would be better.

Either way, it looks like 3-in-1 engine motor oil is listed as "SAE 20", I would try whatever xW-30 you may have laying around, and if that doesn't help, move to a grease.

The spherical bushing looks like this (It's not the actual bearing in my fan, I pulled the image off the internet):

1469749769565a88a5d7bc7.jpeg


I've noted your recommendation for xW-30. I found an old thread on this forum where SAE 30 is also recommended for a fan repair:
https://bobistheoilguy.com/forums/threads/electric-motor-bushing-lubricant-suggestions.189184/

The thread also recommends that it be 'Non-Detergent' and 'German Castrol'. But 3-In-One is recommended as well.

I'm thinking the fan might be squealing on high speed because the 3-In-One oil can't maintain a film between the axle and the bushing at that speed. So maybe a heavier oil will better maintain a film.
 
you might have some excess play in the bushing now. if it is, i would pop the bushing out and replace it seeing you are adept at taking it apart. they are only a few dollar and can be had from grainger or the like.

this is how i fixed a portable air blower . the front bushing was so egged out that the cage was hitting the enclosure. $3 bushing and a hour or so and it works like new. they are $350 new

I would replace the bushing but I've had a hard time finding a place that sells them. (See photo attached to my previous post for what it looks like.) I couldn't find them on Grainger's website either. Perhaps I will phone them. It seems the only place I can get them is from China from sellers like AliExpress.

The fan is back together now, but when I had it apart I don't recall much play between the bushing and shaft, but I didn't check this specifically. did notice that the bushing and shaft were both scored a bit though.
 
I have this fan, though mine has the Lasko label. It's a great fan.

I have helped fans with failing bearings by using the Tri-Flow lube that I use on bicycle chains. Does the PTFE help? I think so, in that it feels that I go longer between lubes, but I have no hard data.

Out of curiosity, do you happen to know if your Lasko fan has ball bearings or bushings? The Air King documentation for the 9155 states that it has ball bearings, but actually it has bushings.

I had a bushing issue with my bathroom ceiling fan several years ago. I cleaned it up and re-oiled with Dura Lube (bottle with thumb pump on it). Dura Lube is a thicker oil and I think it has teflon in it too. Anyway the bathroom fan hasn't needed oiling for about six years now, and I think there is play in one of the bushings since I can hear a faint low-frequency rumble when it runs. So maybe the thicker oil and/or teflon works well in bushings even when they have play.
 
Out of curiosity, do you happen to know if your Lasko fan has ball bearings or bushings? The Air King documentation for the 9155 states that it has ball bearings, but actually it has bushings.
Sorry, but I don't know. I haven't had to tear into it to that point yet.
 
If you can remove the bushing i think you can place them in a pot with hot oil and that helps them re absorb oil

I actually did this when I had it apart. To conserve oil I put the bushing in an aluminum bottle lid filled with oil, then put the bottle lid in a salmon can with about a half inch of water in it. I put the can on my kitchen stove and let it simmer for about three hours close to the boiling point of water, replacing the water that evaporated as needed.

But I'm not sure if the bushing is sintered bronze. I don't see the granules of bronze when I look closely at it. I understand that the oil bath is only needed for sintered bronze so I wasn't sure if it was necessary.
 
I have had excellent results lubricating small-motor bearings with Field Controls SWG Super Lube. I don't know what's in this stuff -- or what makes it so expensive -- but it really works well:

 
Sorry, but I don't know. I haven't had to tear into it to that point yet.

For future reference if you do take the fan apart, note that the nut on the end of the axle holding the fan blade on is reverse threaded.

I didn't realize this, so when I went to remove it I accidentally tightened the nut down and ended up cracking the hub of the fan blade. The blade still works and is balanced but it still sucks that I cracked it.
 
I have had excellent results lubricating small-motor bearings with Field Controls SWG Super Lube. I don't know what's in this stuff -- or what makes it so expensive -- but it really works well:


It looks like this stuff is designed for fans with sleeve bearings that operate inside the chimneys from oil and gas furnaces. So I imagine this stuff is designed for very high temperature service and would be practically indestructible if used at room temperature.

Are you an HVAC technician that services a lot of fans with bushings?
 
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