Quick Tip: Quieting computer fans

Does your computer sound like a supersonic jet somehow hovering directly over your workspace? Does your computer make odd scraping noises, often accompanied by random crashes? Check out this [protofusion] quick tip.

Classify the problem: Are your fans loud or do they make scraping noises?

Scraping Noises

Scraping noises are often caused by bad bearings, whether it be an oil-sleeve bearing or a ball bearing. Take the label off of your fan, if you see a bearing surrounding the shaft, then you do NOT have an oil-sleeve bearing.

Oil sleeve bearings: Place one drop of light oil (sewing machine oil works quite well) on the spindle, replace the label, and let the fan run for a few minutes. Do not over-oil. If the fan is still noisy, remove the clip from the end of the shaft (if present) and detach the fan blades from the coil/case assembly. Ensure that the spindle and sleeve are clean, then re-assemble and oil.

Ball bearings: Place 1-2 drops of oil on the bearing(s). This may have limited success. If it fails, you can try flushing the bearings with oil, drying with paper towel, then putting on a single drop of oil.

Loud

Have loud fans? Chances are you need to just replace them or throttle them.

Throttling: Check out your bios for settings related to “Quiet n Cool” (for AMD CPU fan throttling) and PWM settings for other 3-pin fans on your system. Don’t have the options or 3-pin fans? Throttling can be done manually with rheostats and resistors, just make sure you don’t over heat your system.

Replacement: Check out eBay or your local junk drawer for any fans that may work as decent replacements. Feel free to use overly large fans on small heatsinks, such as northbridges; if positioned correctly, these may render decent results. Warning: Don’t try this with graphics card heatsinks, as they get much hotter than the average northbridge under load. For case fans, try and get larger (120mm) fans if your case accommodates them. Larger == less rpm == less noise + good airflow.

Any questions, comments, or criticism? Feel free to leave some comments.

About Ethan Zonca

Ethan is a computer engineer and open source hardware/software developer from Michigan. He enjoys AVR and linux development, photography, mountain biking, and drinking significant amounts of home-roasted coffee. Find out more at ethanzonca.com.