Cheap easy Thermostat mod
 

I was tired of the sound of my radiator fan, so I bought an automotive adjustable fan thermostat at shucks, for 20 bucks.
It can be adjusted to trigger below 70F.
It is very easy to install, just a little bulky. It has a capillary probe (bulky too) that I taped on the side of the water hoose coming out of the CPU water block.

Very easy mod, efficient to cut the noise down.

It is actually susprising how little is the fan switched on by the thermostat.
In normal uses, like browsing the net, it never comes on. My heater core is on top of the case, so natural convection must be enough.
As soon as I start playing or watching videos, it kicks on within a minute or so. Makes me wonder how much can a passive radiator do. The whole side of the computer case should be an efficient radiator. There is an article on this at Overclockers.com

The thermostat I use is not the best for this useage though. With about 10 C of hysteresis, I must adjust it at least that amount above ambiant to give it a chance to switch off.
Oh well, I stepped back my overclock a bit and now enjoy silence.

This is interesting. An automotive adjustable thermostat you say? You should post a link or take some pics...

I couldn't find a link or a clear pic of the thermostat.
I don't have a digital camera, so I scanned it. I have the jpegs ready.

How do you attach pics (it has being 1+ year since I posted here)?

The thermostat is made by Hayden Automotice, part# 226203