Karl`s PC Help Forums

DIY Repair To CPU Heatsink Fan Question
JackInCT - 11-4-2015 at 19:09

This a question re a DIY repair to my desktop PC AMD processor air cooled CPU heatsink fan.

So the CPU fan stops turning (I have a small utility installed that shows in sys tray the temp of each of the 4 processors).

For a while I was able to manually flip & turn the fan blades (which meant taking the side cover off the PC) so that they would, with enough flips, spin fast enough to keep the temp down; that work-around stopped working (not to mention that it got real old having to do that).

I did the usual YouTube re fan repair (CPU and other types), and discovered that there are various ways that the fan, and its shaft (rotor), are attached to the fan housing (I figured maybe all that it needed was a good cleaning); anyway since the fan had stopped turning, I figured a homemade repair couldn't ruin anything that wasn't working at all. Well it turned out that the blades, and its rotor shaft, were simply forced inserted inside the fan housing, i. e., it just popped in (and of course out to remove it). Obviously a top of the line premium item.

But sooner or later (more like sooner), the fans slows down and then stops (including not starting when I turn the PC on). Over the succeeding weeks I have tried a variety of lubricants (to coat the shaft/rotor), and they all work rather well (as in like new as evidenced by the temp utility)--for a while. I have no idea why their life "span" is so short, i. e., the system is not overheating. I have tried sewing machine oil & garage door silicon lubricant (and yes I gradually increased the quantity that I was applying). Given the short term nature of my results, I'm ready to try grease. By the way, I don't think that there is any real danger that any lubricant that I use will catch on fire (I'm using tiny amounts).

I'm wondering about using the kind of grease that's used to lubricate a car's suspension (that pretty thick stuff that car shops used)--BUT there are all kinds of grease in use in the real world (such as petroleum jelly)? Any alternative ideas to car grease?

Final note: there are NO ungodly noises being make by the CPU fan when it's running, i. e., based on the lack of noise, I don't think that I have an 'unbalanced' shaft & that's the real reason why the lubricants aren't lasting very long.

victor - 11-4-2015 at 19:36

I would hazard a guess that although you said it is cool running the friction on the spindle is creating heat so suggest you need high temperature grease.

JackInCT - 12-4-2015 at 00:03

Originally posted by victor
I would hazard a guess that although you said it is cool running the friction on the spindle is creating heat so suggest you need high temperature grease.

Your suggestion got me searching Goggle and most of the hits for high temp grease were supplied by auto parts type stores, and those would be readily available in my locale.

In addition, the auto parts hits got me thinking (for the first time) about using motor oil. Any idea of the negatives about using motor oil?

I also should have mentioned that my PC is NOT (and never has been) overclocked, etc.,. It came, originally, with a CPU heatsink heatpipe setup that I presume has kept the whole system considerably cooler than a "typical" non-heatpipe system (not to mention that the thermal paste has been doing its job all along).

scholar - 12-4-2015 at 02:01

I used to have a great auto mechanic who insisted lithium grease was best for durable, high temperature applications.

Silicone grease is often used in dielectric applications (e.g. to put a little on your spark plug wire ends for better conductivity). If there was any chance some would get out of place, that could be a reason not to use silicone.

Hmmmm. Why is it "silicone" and not "silicon" in the articles I checked before posting?

LSemmens - 13-4-2015 at 01:31

For the amount of money spent on grease, etc, would it not be much cheaper just to replace the fan?

JackInCT - 13-4-2015 at 13:08

Originally posted by LSemmens
For the amount of money spent on grease, etc, would it not be much cheaper just to replace the fan?

Yes, it would be, BUT the company that made the fan as noted on a label on the fan does not seem to exist any longer.

Plus there is an additional issue of how the fan is mounted to the heat sink; INSTEAD OF bolts, the fan is mounted to the heat sink [there is a gap] with 4 VERY soft rubber nibs (not sure that's the standard term for them), i. e., there is a gap between the front and back of the fan 'faces/wall' [a kind of sandwich] that these nibs have to be fed through (my guess is that these rubber nibs are an attempt to dampen fan noise by reducing vibration, i. e. #2, a kind of shock absorber system (and there's nothing on the heatsink re a brand name).

Computer fans of ANY sort are not carried by any local brick and mortar stores, i. e., it's online availability only. It's especially difficult to tell from a low res picture, and product description (very brief) just what fan would fit.

AND going through to the idea of replacing the heatsink (which always come with a fan) is a show stopper re form factor; I tried to figure that out, and I find it impossible to 'predict' (since heatsinks come with dimension measurements from online vendors), a way of precisely determining whether the size would clear all the hardware installed in the vicinity of the CPU; while all vendors have excellent return policies, the customer bears the cost of return shipping charges; those charges are not cheap, and if you have to do more than one return......

LSemmens - 13-4-2015 at 14:03

Make and model of the PC, better still, the MOBO would go a long way towards sorting you. CPUs are fairly generic, as is most cooling, unless it's a "supermarket" PC built to a size and budget.