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A fan with heat problems?!

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Dec 18, 2000
Just bought a Sunon 120mm x 38mm AC axial fan (DF200A, P/N:2123XST, aluminium cased) for a bargain basement price of US$9. But when I got home I suddenly believed less in the Sunon brand name. This particular fan, having an induction motor (and the inefficient shaded-pole type), had some serious problems:
1. Vibration: Place it on a lightly constructed table or shelve and watch the other stuff jump up and down. I wouldn't even place it on the floor w/o any form of vibration isolation (eg. foam mouse pad).
2. Lubrication: Yup, Sunon gave this particular fan a rather generous dose of lubricating oil sintered into the sleeve bearings. Not only can you smell the oil in the airstream but it leaves visible residues on the inside of the fan's surrounding aluminium case.
3. Heat: CAN YOU BELIEVE THIS FAN OVERHEATS?? After about half-an-hour of running, chattering sounds can be heard from the hub of the fan and frankly it's damned irritating if not worrying. Turns out that when it runs after a certain time, the bearing clearance get enlarged enough due to the copious amounts of waste heat (this fan need 21W to output 100cfm -in contrast, my 120mm Evercool takes in only 4.8W to output 80cfm) that vibrations due to the loosened fitting occurs. Fortunately I've solved this by gluing a heatsink at the hub of the fan. Can you believe this.

I'm tempted to return this fan but I think there wouldn't be much of a chance -bought it at some mom-and-pop shop and it was the last unit available. Even if the problems above are actually rare, I still wouldn't recommend anyone to buy an AC fan for casing ventilation due to the inherent inefficiency of induction motors -you may inadvertantly heat up the inside of your PC instead of cooling it.
Sounds like you just got a lemon. I have yet to see a Sunon behave like that. To be honest with you it sounds like there is something loose.

Vibrations, noise, and heat are a good indicator of a bad bearing. Take the sticker off and see if there is a nut inside the hole, if there is, see if its loose.
Yeah that sounds really screwed up. I have a sunon 128x38 and it had little or no vibration and runs perfectly.
I have a sunon 60mm and it works wonderfully. This is ball bearing though. I've never had very good luck with sleeve bearing units.
Were those Sunons AC or DC? Jetset, out of curiosity, do you have the product number of your Sunon? Is it the same as mine (P/N:2123XST)?