[hutzlibu]

Opening it up and vacuum cleaning the fan from dust also can do wonders with old and "broken" laptops as a first step. Tiny bit of WD40 in the fan mechanic is the next, then thermal paste, then replacing parts.

(Advice, prevent the fan from spinning while doing vacuum)

[HankB99]

WD40 - Nooooo! It gets gummy. Use a proper lubricating oil. Or replace the fan.

"Pro tip:" Do not direct the output of a strong air stream (e.g. the kind used for automotive work) at the fan as it can de-blade the fan.

[hutzlibu]

Good to know, but in those few fans I used it for, it worked so far ..

[BizarroLand]

And if you do that anyway, don't be a dingus.

Disconnect the fan cable from the socket so that the motor doesn't send pulses of energy back into your laptop. It probably won't harm it, but better safe than sorry.

[malfist]

Motors have flyback diodes. Otherwise they'd burn out things every time they turn off

[BizarroLand]

Not in most laptops they don't.

https://forum.arduino.cc/t/is-a-flyback-diode-built-into-lap...

"You will find those fans are brushless DC fans, they are controlled by an inbuilt driver circuit and as such do not need a flyback diode."

[malfist]

So you "disprove" my statement with some rando on the Arduino message board that has less than 20 posts in their lifetime?

What makes you think they're an authority?

Brushless motor still have fly back voltage that has to be clamped. You may not need to install a diode in the fan, but I can guarantee you that this "inbuilt driver circuit" has such a diode.

And if you read the linked thread a bit more you'd see where they test it and it does produce -100V at shutdown. If there wasn't a flyback diodes it'd be burning out ic's left and right

[BizarroLand]

Why would I accept your word without any backup?

Its on you to provide evidence of your claim, not on me to disprove your unfounded claim.

[Modified3019]

As mentioned by another commenter, many of the compounds in WD-40 “dry” out, either by evaporation or oxidation (turning to lacquer/sticky goo like what you find in the oven). WD-40 is meant for penetration and water displacement, not desirable for achieving long term lubrication.

An example of something better to use is 3-In-One Multipurpose or Motor Oil.

Another FYI is that oils break down grease, which is found in bearings (WD-40 aggressively so), so it’s not generally desirable to apply oil to bearings, unless it’s already having issues and you just need some additional life out of it.

[Night_Thastus]

As someone else stated, WD-40 is a solvent and a degreaser. It is designed to displace water.

In fact, for bearings which need grease, WD-40 can remove the very thing that is keeping the bearings from wearing out!

If the fan is very old and no longer works properly, it just needs to be replaced.

[hutzlibu]

"If the fan is very old and no longer works properly, it just needs to be replaced. "

Sometimes it is really complicated replacing them with a danger of damaging stuff, if you have no routine. Then using something to spray is easier to fix it for some time. It helped in my cases, even though I will definitely try something else next time ..