Thinkpad T61 Pulsing Fan Issue

[xur17]

I have a Thinkpad T61 that I just recently replaced the fan in (it was dying, and making loud grinding noises when running).

The new fan works fine, but it seems to pulse (turn on for ~5 seconds, then turn off for ~5 seconds, and repeat), which is rather annoying / irritating.  This occurs in both windows and linux (ubuntu)

I don't think this was hapenning before I replace the fan, but it is hard to know since the fan was having other issues.

Is there some easy way to fix this, or to force the fan to a specific speed?

[Cloakedboltz]

That's odd. Maybe that fan is just so good that it only needs to give a vent every 10 seconds, quickly heats up again and turns back on.

[xur17]

---

Cloakedboltz wrote:
That's odd. Maybe that fan is just so good that it only needs to give a vent every 10 seconds, quickly heats up again and turns back on.

---

I'd rather it just stayed on the whole time instead then.

[lead_org Microsoft MVP Contributor]

did you have proper coat of the thermal paste on the heatsink? also did you get the fan new? and is it an original part?

You can install software like TPfancontrol to control the fan speed and behaviour.

[Cloakedboltz]

---

lead_org wrote:
did you have proper coat of the thermal paste on the heatsink? also did you get the fan new? and is it an original part?

You can install software like TPfancontrol to control the fan speed and behaviour.

---

That's smart. Usually replacing the fan means replacing the heatsink unit too.

I suggest trying to wipe off the thermal paste and putting fresh one.

[sauerquint]

Well, if you haven't ever replaced the fan without doing the heat sink then you shouldn't be making 'smart' comments like that. There is a separate part number for the fan right there on the Lenovo site.

[TuuS]

I believe when purchased from lenovo, the fan and heatsink are only available as an assembly, but you can buy only the fan from other sources. Once the heatsink is removed it's a simple matter to install a new fan. 

Regarding the OP questions...    if the cpu temperatures are changing that irratically, then I'd suspect there is poor thermal contact, so perhaps you should try cleaning the thermal paste and using Arctic Silver #5 brand. Be careful not to use to much or to little, when properly applied, it should keep the fan to minimal levels. On mine I have a hard time telling when it's running, I can only really hear it if my cpu get's stressed and it kicks into high gear...   perhaps that is what's happening in your case, you're only hearing it when it runs on the highest speed.

As mentioned, thinkpad fan control (tpfancontrol.com) will help you monitor the temps and the running speed. 

[lead_org Microsoft MVP Contributor]

the fan/heatsink unit is purchased as a complete unit, when i mentioned did you purchase the fan new (i was actually referring to the complete unit).