MBP 2011 running hot

[MacUse-R]

I have a MBP late 2011 which has all of a sudden started to run hot, earlier it always had a low temperature of around 47 - 60 degrees Celsius, now it often runs at about 75-90 degrees Celsius even without any particular CPU heavy work.
The MBP has 8 GB RAM and an i5, 2.4 GHZ processor, and is running High Sierra. The MBP was fine on High Sierra earlier.

When I used TG Pro software it first said at the Fan diagnostics section that the fan didn't appear to work normally, I reset the SMC and it resolved that error message, at least so far. I once had the fan stuck but I fixed that, now the fans are running (somewhat).
First when this problem started the fans only run at slow speeds all the time, around 2000 RPM, but now it picks up speed when the temperature gets hot, but it seems the fan is slow to respond to the temperature rises, and it seems it doesnt respond early enough but instead the fan only increases speed after the temperature has gotten really hot, and also it doesn´t take the temperature down low enough.

I have no programs or processes that is using much CPU or memory according to the activity monitor, actually the CPU often uses only around less than 10 % and memory often uses around 4 GB out of the 8 GB available.

Any ideas what can cause this problem all of a sudden? And any ideas what to check or do next? I find it strange that it happened from nowhere?
Some help and ideas is appreciated.

 

[tubeexperience]

Have you cleaned out the fans?

 

[hajime]

I have 2010 model so it may be similar. Fans are clean and I replaced the thermal paste. Still heat and fan issues.

 

[MacUse-R]

Have you cleaned out the fans?

Well I tried but its a bit hard reaching between the fan blades. But when looking at the fan it looks pretty clean, maybe a little bit of a very thin layer dust in a few places between some of the blades.

So I dont know if that could affect the temperature?

I´m wondering if it could be the fan sensors that aren't responding correctly? Since It seems the rise in fan speed is slow to start and doesn´t cool down the MacBook Pro properly? And also the fan slows down before the temp is low enough

I did the Apple Hardware test and it reported no problems, but I did the fast hardware test, don´t know if the longer and more thorough hardware test is needed to catch more types of problems?

 

[prisstratton]

You could look at replacing the thermal paste. I recently took apart my MBP (see my sig. - same gen. as yours), and I was glad that I did. The thermal paste looked like it had been put on with a garden trowel, it was all over the place.

I was not actively monitoring the temps. on my CPU/GPU, so I cannot say whether this helped. But, given how it looked, it has to be better than what it was.

 

[MacUse-R]

You could look at replacing the thermal paste. I recently took apart my MBP (see my sig. - same gen. as yours), and I was glad that I did. The thermal paste looked like it had been put on with a garden trowel, it was all over the place.

I was not actively monitoring the temps. on my CPU/GPU, so I cannot say whether this helped. But, given how it looked, it has to be better than what it was.

Where exactly is the thermal paste located, over the CPU and under the fan, or where?

I noticed that the high temperatures is always on the different CPU cores and on the PECI GPU.

 

[duervo]

If there were no changes in your workflow, or no updates installed recently, then I can’t see it being the paste if the temperature change was sudden like that. I’d look at the heat sink if it were me. It may have developed a crack in it. They’re pretty cheap, but keep in mind any that you would buy will likely be used.

 

[prisstratton]

Where exactly is the thermal paste located, over the CPU and under the fan, or where?

I noticed that the high temperatures is always on the different CPU cores and on the PECI GPU.

The thermal paste is between the chip(s) and the heat sink. If you follow the guide from iFixit it will become very obvious when you take off the heat sink.

Please see the tear down for my MBP, here:

https://www.ifixit.com/Guide/MacBook+Pro+17-Inch+Unibody+Heat+Sink+Replacement/3446