Case fans noisy, then quiet!

[waylo]

I had a computer built for me several years ago through one of the online retailers. No problems for the most part. I requested extra fans put into the side panel (2).

For ~1 year, no problems. Then, starting ~1 year ago, whenever I boot my computer, these 2 side panel fans make a horrendous racket. No cables or anything are hitting the fans, they're just noisy as heck. About 1-2 minutes after they start up, about the same time Windows pops up, they quiet down to what I'd consider normal.

I've cleaned out the dust as best I could (maybe helped?). Do they just need oiling?

[amdkt7]

If you have cleaned all the dust off the blades then the next thing to try is to peel the lable off the motor to expose the armature shaft and apply a drop of oil (3-1 oil would be best). If that does not do it than replacement is in order.

Sounds like cheap fans to have problems so soon.

[elroy]

Your fans are going south on you.
Look here for new ones: www.nexfan.com
I always order a few 80mm case fans when I get stuff from them. Even their cheapo $1.50 fans last a long time and are quiet. I just put one in an Enermax power supply yesterday because the original fan was making a horrendous racket.

[RedFury]

most case fans have a sleeve bearing, which is a garbage bearing for long term use. they have a tendancy to lose their lubrication and if the motor shaft goes crooked for some reason, you're going to get a lot of wear on one part of the bearing causing a squeal or noise. I always try to buy ball bearing fans whenever possible for that reason.

[waylo]

Finally detached them from the case... 2 Raidmax ball bearing fans. Still quite a bit of dust on the blades. But I'll peel the label off to oil and try again. Weird that they quiet down after ~2 minutes of "warm-up."

[RedFury]

Could be that the bearings are getting "stuck" on a groove or notch ( possibly melted by an overheated bearing when it came to rest ). I'm sure the bearings are starved for lubrication.

Good luck, hopefully the 3n1 will solve your woes.

[DanU]

Originally Posted by waylo

Weird that they quiet down after ~2 minutes of "warm-up."

This is typical behavior for an oil-starved sleeve bearing. The noise you hear is probably due to the shaft wobbling in the bearing. THAT'S BAD, because it puts stress on the shaft and the bearing, and wears them both out. As the bearing warms up, some oil flows back into the shaft-bearing interface, reestablishing proper operation.

BTW, DON'T use the regular 3-in-1 oil in the red can. It's good for general lubrication, but not that great for sleeve bearings. 3-in-1 makes another oil in a BLUE can that's specifically formulated for electric motors: http://www.wd40.com/Brands/3in1_product_info.html

Non-detergent SAE 30W oil is also commonly recommended for sleeve bearings.

I've tried regular automotive 10W-30 a few times cause that's what I had lying around at the time. It worked for a few weeks but eventually the bearing runs out of oil again. My guess is that the viscosity wasn't high enough to "stick" to the bearing. Plus the oil was formulated for internal combustion engines, a very different environment from electric motor sleeve bearings.

[waylo]

DanU:

Thanks again. Followed your instructions to the letter and the first run at least is smooth/quiet. This is the 2nd consecutive issue you've settled with my computer on this forum!

[DanU]

Hey that's great! What oil did you use?

[waylo]

The 3n1 motor oil (blue label). Walked into Ace Hardware and found it almost immediately. Funny, since this local store looks like such a cluttered mess.