Fan stops working aproximate 20 minutes after cold start.
Hi, I have a 6 year old MacBook Unibody (late 2009) which worked well till now, thanks to fast SSD and new ifix Battery). The OSX version is 10.11.4 (El Capitan).
Yesterday it shutted down without any warning. After starting it again the temperature (CPU Die) was about 120°C and the fan was not working (0 rpm). I turned it off again to let it cool down. I also opened the MB and cleaned the fan following the fan replacement instructions with disconnected battery. I also did SMC and PRAM reset. I was not able to run Apple Hardware Test (D key at startup sound).
Anyway, after a cold start it seems to work well again, the fan was working too. But about 20 to 30 minutes later iStats menu indicated again 0 rpm I was not able to hear the fan and the heat went up slowly.
Today, after a cold start I got the same results, fan worked. I installed a fan control app to raise the fan speed to keep the computer cold, as I thought it might be related to the temperature. I was able to get it to 6000 rpm (where the spinning was hearable, without strange noise). About 20 to 30 minutes later the fan stopped working again. The fan control app was not able to control the fan speed, it showed 0 rpm.
I am still able to use the computer with only a few programs open and constantly monitoring the temperature - to not allow it to get over 90 °C. I was using a hairdryer to blow cold air into the exhaust on the back side to be able to finis the time machine backup (otherwise the temperature would have risen over 100 °C and the machine probably shut down before finishing backup.
I am wondering if changing the fan would have sense, as it seems to work, at least after a cold start. The fan does not make any strange noises and when I was cleaning it, I also verified that it spins well. Could it be a failure in the fan control (chip)? What does it need to fix that - hopefully not a logic board replacement. May there be a workaround (for example to connect the fan somewhere else to have it run always)?
I would appreciate any help/information on that. I need the macbook to work. I am currently living in the north of Argentina (next service provider is more than 1000 km away from here). The macbook should at least continue to work until new MacBooks (Pros) with Intel Skylake are are available.
Is this a good question?