Processor fan going crazy!

By weirdcity
Dec 24, 2006
  1. Well, I built my cpu about a year and a half ago, and it has been running just fine until about a week ago after I watched a movie on my cpu, and it ubruptly shutdown...

    At first I didn't pay it much attention until the system kept shutting down after about an hour of running or so. Then I noticed that the case began to vibrate, and there was a new noice that seemed wrong. By now when I wanted to turn on the cpu it would take me like 5 tries to keep it on. Finally, two days later I decided to open up my cpu and turn it on. The processor fan seemed to be struggling to start, and the system shut down immediately.

    The second time I tried the fan didn't struggle but after a few seconds it started to wobble again and the system turned off once more.

    Now, I'll admit I hadn't dusted my computer in like 6 months, so I cleaned it figuring that this might be the problem. Nope. Fan continued to struggle.

    So then I tried removing the fan off the heatsink in order to see if the fan was having problems, or there was something else. The fan worked FINE once it was off the heatsink. I cleaned the fan more thoroughly and reattached it to the heatsink. The system turned on immediately. But about an hour later it turned of again, the noise was back.

    Now my cpu is running with the fan over the heatsink, unattached, and the tower is lying on its side so the fan won't fall off the heatsink. The fan only appears to struggle when it attached to the heatsink...

    So here's my question:

    Is the fan the problem, the heatsink, or both?

    I read about loose heatsinks... but mine won't budge so I doubt that's it. If you go t ANY idea, let me know.

  2. raybay

    raybay TS Evangelist Posts: 7,241   +9

    I'll vote for the mounting posts to which the CPU and the heat sink attach.

    Many of the mounting posts to which the CPU fan attaches are broken in shipment, and not noticed at installationi. Check all that stuff systematically
  3. JimShady23

    JimShady23 TS Maniac Posts: 373


    Could be that the bearing in the fan is going out, this happens all the time, if the fan is sitting in a certain position it will work, in another position it will not. side to side, up and down ect. You may just need to replace the fan.

    The speed sensor on the motherboards CPU fan connector is just detecting that the fan isnt spinning at a acceptable RPM and shuts your system down for saftey so no worries there.

    You can get a decent replacment fan online or at a local shop cheap or even better use this as an excuse to buy a better coolling solution. $20 goes a long way now a days for air coolers.
  4. raybay

    raybay TS Evangelist Posts: 7,241   +9

    Not likely, if it is a good CPU fan to begin with... as the bearing will work at any angle in a good fan.
  5. JimShady23

    JimShady23 TS Maniac Posts: 373


    Not if the bearing is worn or bad...... You can usually tell this by just pushing on the fan. If there is a ton of slop between the fan blade assembly and the rest of the fan bracket that means the bearing is gone or going. (it will seem like the two peices of the fan are really loose.)

    So if the fan is sitting facing down as if it would be when you have your computer case laying on its side it will rely more on centrithical force to spin meaning that it will spin easier.

    When a fan with a bad bearing is sitting sideways as it would if your case is sitting normal the fan has a harder time spinning cause it has to fight the bad bearing more.
  6. raybay

    raybay TS Evangelist Posts: 7,241   +9

    A lot of use had to take place during that 1 1/2 years, but it definitely could happen. Or A bad bearing is possible as well.
    Such an inexpensive thing to fix. Everybody should replace their CPU fan every year or so anyway. $12 to $25 for most coolers is a simple way to put in some current protection. Nearly all of our clients do not replace the CPU fan until it blows.
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