How To Fix A Noisy PC Fan

by ComputerBob

September 2, 2006

This afternoon, I received the following email message regarding a noisy fan in an HP computer:

My mom bought this HP pavillion computer and it works great but after the pc has been on for 10 minutes the fan runs and it sounds worse than a vaccum cleaner and this noise is annoying. Is there any way to fix this problem?

Thank you so much for desiging this web page, your web page is used alot in my web design class.

sincerly,
William

Here is what I wrote in reply:

Hi William,

Thanks for your kind words about my site. I appreciate you taking the time to write them.

Re: the noisy fan in your mother's PC, it sounds like (no pun intended) you may need to power-off her PC, open it up, and give it a good cleaning with a vacuum cleaner. If possible, after you've got her PC open, and before you clean it, turn it back on so you can figure out which fan is causing the noise problem (many PCs have more than one fan). If it's the CPU fan, then you're going to want someone who is comfortable and experienced with removing it and replacing it with a new one, because it is EXTREMELY important to get 100% physical contact between the CPU chip itself and the cooling fan/housing that is attached to it, or the CPU is going to overheat and destroy itself within seconds of being turned back on.

If the noise turns out to be from a normal case cooling fan (3-5 inches across), you can try cleaning it really well to remove any dust, and see if that fixes the problem. If not, you can buy a replacement fan of the appropriate size at pretty much any PC store for $5-$20. It takes 5-10 minutes to unscrew the old fan and install the new one, and just use the same electric wire from the old fan for the new fan.

If the noise turns out to be from the computer's power supply, you cannot repair it, so it needs to be replaced. I would recommend either replacing it yourself, or having someone who has done it before replace it for you. There's usually only 4 screws that hold the entire power supply box in the case, and then you also have to unplug the power cords that go from the power supply to the hard drives, floppy drive, CD drive, other internal peripherals, motherboard, and fans. Carefully remove the entire power supply box from the PC case, being careful to not scrape it or bang it against any of the memory cards or other internal components. Take the noisy power supply with you to a discount computer store and find a new power supply that's the same physical size and at least as many watts as the current one (usually 350-500 watts). If you go with a generic power supply, it will probably cost around $30. If you go with a name brand, high-wattage power supply, it can cost $100 or more.

Of course, if the PC is still under warrantee, then call HP and ask them to fix it (or tell you where to take it to have it fixed for free.)