... I also red that there is a software for fan control - but still can t find the proper one....
That software is TPFanControl062
. I set up my CPU power setting to adaptive and adjusted the limits of tpfc62 so that fan doesn't work at all most of the times. My CPU temperature wanders around 50-55'C and my X61T is ultra quiet. Since the fan is less used, I expect it to live longer.
When you are installing the fan be careful not to bend the mainboard and make sure the chip surfaces are ultra clean for clean adhesion. My experience from Sony Vaio SZ-1 is that the connection between chip surfaces and cooling equipment makes great impact on cooling efficiency. Sadly I remember servicing old Thinkpads where previous service guy forgot to remove protective folio on the replacement fan before installing them. Thank God those CPUs didn't get that hot.