Computer Fan Grease?

[JZiggy]

Hey guys,

This is actually related to a work project where I'm trying to understand the resistance of certain plastics to greases or oils that may be found in computer fans. Any idea what sort of grease comes in these fans?

Also, any idea if this is truly a Mobil product?

http://www.drivestar.biz/mobil-computer-fan-grease-5g-p-2719.html

Feels a little sketchy. There are similar little tubs sold on eBay for a few bucks.

My initial assumption would be a silicone based grease, or else just oil/graphite loaded bronze bushings.

 

[nthach]

That looks like Mobil Polyrex EM grease, typically used in electric motor bearings.

 

[bubbatime]

It is thermal grease. It helps the heat-sink pull the heat off the processor. For the application, I would be tempted to spend a little more and get a better product.

http://en.wikipedia.org/wiki/Thermal_grease

Edit: I see you are talking about the grease that is actually in the fan, not the thermal grease. Never mind.

 

[dparm]

I have no clue what grease they use. The ball bearing design in most of those is getting very sophisticated to keep the noise levels down.

 

[ezombie]

I'd like to know too. It's definitely some kind of semi fluid grease which I can't find.
I've been using 100-150cSt NLGI 2 grease in these fans and and it seems to be fine. The reduction in rpm versus using oil is up to 8%.

 

[miro]

Originally Posted By: dparm
I have no clue what grease they use. The ball bearing design in most of those is getting very sophisticated to keep the noise levels down.

There is nothing special with this grease. You can follow the SKF ball bearing instruction.
1. Select base oil according to DN
2. Select NLGI #
3. Define quantity of applied grease - very important step. SKF has very good document about it.
4. Define the frequency of relubrication. Again SKF has fantastic document.
Needless to say that relubrications can be done only on good quality bearings. It will not help on broken/ with plays bearings.
My experience is to use high quality fans. Most of them comes from Japan. They used sealed for life grease- most likely polurea based. You don’t have to take care. I have a fans from 2002. They run on my servers 24/7. From time to time I have to clean dust and they still works as day 1. However they were not cheap, but in long run they are cheaper. In the mean time I have changed 3 servers but I still use the same fans

 

[ezombie]

DN value is very low in these fans. In my case below 10000, I use 8cm sleeve bearing fans. But low viscosity grease should always be the choice here because the motor has very little power.

 

[miro]

Originally Posted By: ezombie
DN value is very low in these fans. In my case below 10000, I use 8cm sleeve bearing fans. But low viscosity grease should always be the choice here because the motor has very little power.

I think that you mix two thinks.
Base oil viscosity and consistency.
Low DN application use high viscosity oil and low consitency grase e.g. nlgi 00,0,1
I forgot to mention that DN says not everithing. Load and temperature condition must be taken into account too
Sleve bearing requires different consistency than rolling bearing.

 

[ezombie]

Originally Posted By: miro

Low DN application use high viscosity oil

That's exactly why I wrote that in this case, no matter how low the DN value is, low viscosity grease is preferred.
I do know the difference between consistency and viscosity. It's just that here we don't want to put stress on a weak motor. The lower the viscosity, the lower the drag on a tiny motor.

 

[miro]

Originally Posted By: ezombie
Originally Posted By: miro

Low DN application use high viscosity oil

That's exactly why I wrote that in this case, no matter how low the DN value is, low viscosity grease is preferred.
I do know the difference between consistency and viscosity. It's just that here we don't want to put stress on a weak motor. The lower the viscosity, the lower the drag on a tiny motor.

OK. The load in this application is very low. So, the low viscosity grease will be fine/e.g.below ISO100 /
Needless to say that consistency NLGI 0 or 1 will be ok too

 

[compaddict]

I have used Redline CV-2 and the stuff before it on computer fans for years and years. No problems and I have greased over 100 fans.

 

[ezombie]

Did you need to regrease any of them over years? How is the longevity?

 

[compaddict]

Some of the first ones with the early grease came back after one or two years. Most never came back for the rest of their service life.

 

[camelCase]

I thought a lot of computer fans were coming with bearings similar in design to air bearings like that found within hard drives....?

With them being so cheap, why would you waste your time greasing one? When they start to make noise, its usually because they are off balance at that point. I'd, personally, think that replacing them is a better option than greasing them. Time value of money and all that stuff.....

 

[ezombie]

Some people do it because they're lazy to go out to town and get a new one and some do it because they enjoy it, like me.
I hate to throw a working thing away when I know there's a way to extend its life.

All fans I have, should have been long gone by now, but with a little help of grease or heavy oil they've been spinning for years. And who doesn't like to spend some quality time hanging with greases and oils?

 

[OVERKILL]

Yup, I've pumped some life back into a couple of fans on my Lian Li that developed some noise about two years ago. A bit of M1 0w-40 placed in the bearing cavity with a syringe and put the plug back on and the sticker back over it and they've been quite since.

 

[camelCase]

Maybe just try moving it's location too? Instead of mounting it vertically, mount it horizontally to reduce any stress on the bearing joint?


If it is an air bearing design, idk if any grease will help.

Really... I think any grease would be too much for a computer fan. A real lightweight oil might be best?

 

[ezombie]

Horizontal mounting of pc fans will significantly reduce their lifetime. That goes for sleeve bearings which is the most common type.
Lightweight oil doesn't stay in place, it escapes quickly and forms a thin film which sometimes isn't enough for already worn out bearings. There are special designs that can benefit from oil like rifle bearings and types with grooves for oil circulation. But majority of pc fans is a simple sleeve bearing type and grease does very good job here. I switched from oil to grease. Also, I've been seeing new fans filled with semi fluid grease, not with oil.