Solved CPU fan cyles fast/slow - annoying noise

[heritage]

The computer is three years old but is fast and runs Win 7 ultimate. It just started making an annoying noise. It is definitely the fan on the mother board very close to the CPU (Intel Pentium 4 something). The cycle is faster than once a second and mimics a hard drive write. Touching the mother board clearly isolates the vibration and one can see the fan speed up and slow down. At first I thought something was overheating but it does this as soon as the computer turns on and continues indefinitely.

OK - "Replace the fan" That is a major nuisance and I am hoping that some really clever person has a neat solution; e.g. oil it or twist the board (scary) or something like that.

There are some old threads about noisy fans but those descriptions don't seem to fit my situation.

Thanks in advance. I have gotten some really clever advice on this forum.

 

[linnemeyerhere]

heritage welcome to SF.
I would first unplug the power cord to the back of the PSU then remove the side panel and then carefully check and snug up all the mobo mounts as well as the CPU cooler mounts. Then regarding the fan on the CPU cooler that's making noise I would clean the fan and cooler with compressed air and remember to stop the fan from moving when you dust it off with air. Advise us after cleaning and checking for snugness the noise continues.

 

[heritage]

Success

Amazed by your speedy reply. It popped up on my screen just before midnight and I decided to sleep on it. Since I did several things, I can't be absolutely sure what the problem was.

I removed the fan from the mother board and turned on the computer for a few seconds. The fan continued to speed up and slow down so I don't think it was the mounting screws and certainly not an overheating problem. (?)

I had already cleaned this fan as part of a general refurbishing of the computer. However, while the fan was out I cleaned it with a Q-tip dipped in alcohol since some grimy dust remained. Then I oiled with light machine oil. Not sure that is a good idea but I was desperate.

Back to together and Voila - no noise. THANKS.

(I refurbish donated computers and give them to local non-profits. I am definitely an amateur but I have seen a lot of old computers. I have seen a lot of weird problems. About half I toss but the rest are greatly appreciated. This one with Win 7 Ultimate and a 3.2 GHz processor and 2 GB RAM is much too good to toss.)

 

[linnemeyerhere]

That's great to hear or not as the case may be.....lol.....and many do re-oil their fans but in almost all cases it requires a dissemble to pull a seal and then re-oil.