View Full Version : iMac G4 fan replacement

Sep 22, 2011, 07:46 AM
I replaced the broken hard drive in my iMac G4 with an SSD, so now it runs more quiet, and I guess cooler too. But now I keep thinking the fan is too loud. As the SSD makes the machine cooler, I figure the fan is a bit overkill now.

I can't get programs like G4fancontrol to do anything, probably because there is no heat sensors in the iMac G4. So what I wonder is, can I replace the standard fan with another fan with less rpm or something, that makes less noise?
How much cooler might the iMac be with no mechanical drive, and what fan is therefore a suitable replacement?

I read that the fan should be 92mm, is it so? Will a 3-pin connector / 4-pin Molex connect? Would any of these suit?

Sep 23, 2011, 02:54 AM

A quick question here! I have an 800mhz 17" iMac G4 which I'd like to have an SSD in as well. Where did you get it?

As for the fan, I'd say it's better to keep the original one.

Sep 23, 2011, 06:22 AM
On the net, it was a 3.5" model so it was a bit expensive and not available anymore. You could buy any 2,5" IDE model and place in a 3,5" bracket, there should be some on the net, try eBay etc. Why is the original fan better?

Sep 24, 2011, 01:58 AM
i replaced the white fan with a quiet vantec fan. it's quieter and pushes more air out the top.

Sep 24, 2011, 01:26 PM
i replaced the white fan with a quiet vantec fan. it's quieter and pushes more air out the top.

How quiet is that model, does it make the iMac as quiet as the Mac mini?

Sep 24, 2011, 03:32 PM
I don't know what model the fan is exactly, but it is very quiet and it does push more air out that the stock slotted fan. Plus i don't use the iMac on a regular basis since the graphics card is toast and i need a new logiboard replacement. But when i VNC'ed into it with my G5, i had it on for hours, and i didn't hear a thing. I felt alot of air coming through the top of the dome, so i know the fan is running.

I took out the white fan, installed a 92mm regular fan, using a 3 to 4 pin adapter connected to the hard drive power and that's how the fan runs.. So if there is a temperature sensor for the white fan, it won't read properly.

Sep 24, 2011, 08:20 PM
Could it be the Vantec Stealth fan? Is a 3 to 4 pin adapter needed or will it connect even if you don't have one?
A multicolored fan like this would turn it into a discoball? http://midnightimods.weebly.com/uploads/5/0/5/4/5054569/6839365.jpg?347

Sep 24, 2011, 09:30 PM
I don't know what fan it is exactly, and it just works.

As for the 3 to 4 pin adapter, yes, you will need one, since the iMac fan connection is in reverse. The fan has male pins on it, while regular fans have a female plug end.

As for the LED fan, if that shakes your boat i guess....

Sep 25, 2011, 03:35 PM
Would this work you think? http://www.clickok.se/PartDetail.aspx?q=p:923574
It looks a bit tangled, but I assume if I plug the fan into the 3-pin female, the signal goes to the 4-pin male that must plug into the computer hard drive cabling - is it 4-pin female on the iMac?
Or should I use this one?
It looks like 3-pin female to 4-pin male, or am I wrong?
Or maybe one of these with both 3- and 4-pin at one end is better?
Not sure if the 3-pin connector is female on all of them though.

Sep 25, 2011, 04:09 PM
Either of these ones will do
This one makes the fan run at a full 12V

This one converts the fan to run at 7V

Then you just plug the regular 92mm fan into that cable.

and how you would power the mac hard drive, you just put that in between and then you power the hard drive and the new fan.

Sep 25, 2011, 07:14 PM
his might give you a bit more insight of what you are thinking of doing

iMac G4 Fan Mod (http://dl.dropbox.com/u/1020076/jj/imacg4fanmod.html)

Nov 3, 2012, 07:28 PM
Well, did it at last. With the replacement fan from Arctic it sounds almost as quiet as a Mac mini. At first that is - after using the iMac for a while the fan slowly spins up and is slightly more noisier. I attached the temperature sensor behind the hard drive, but maybe there's a better place that is less hot and thus makes the fan spin less? First I had the sensor placed under the dvd drive, which obviously was wrong, since the fan went to maximum at once. Must've been hot since that's right above the logic board.