Hello, new to the comunity.
I have an Acer Aspire 5542-1297 with the latest Ubuntu Mate. No other OS is installed. 3GB RAM and AMD Athlon II Dual Core.
I disassembled the laptop, clean it, put some new thermal paste and the overheat continues... I can't even watch a YouTube video without going to 100ºC or even more.
What could be the problem. Here are some screenshots:
Any help would be appreciated, thanks in advanced.
Hi. Welcome to the community!
Obvious question, but is the system itself actually burning hot to touch? On some systems, these temperature values can be wildly inaccurate and give a false indication. It depends on the sensors you’ve selected.
Can you view the temperatures in the BIOS? If you can see a different in numbers (eg. 95ºC in Ubuntu, 32ºC in BIOS) you can apply an offset by right-clicking on the applet, choosing “Properties” and then choosing the sensor and then opening their properties again.
There is a way to probe the system for different sensors, which may be more accurate for your system:
sudo sensors-detect
(A package might need to be installed, but I’ve forgotten which one if so)
If it is actually overheating, it could be due to the graphics drivers in use. Some graphic cards/chipsets handle temperature control better under the proprietary driver then the open source drivers, providing it’s an AMD or NVIDIA graphics card. Try changing the driver with the Additional Drivers tool if so.
For “sensor-detect” you need to install the “lm-sensors” package.
I see three temps – 95, 90 and 101. What do the temps represent? One should be
the Radeon, one should be the Athlon and the last one should be the motherboard.
Which one is 101 degrees?
What is the temp of the hard disk?
Is there air blowing out the back of the laptop?
Do you have the CPU throttling set to performance?
I’d expect the plastic to start to smell like it’s burning if you are really “boiling” the cores.
I had the same problem i set the cpu throttling to performance and its still hot but not as hot. you can check out this link to change it permanently. be careful to read all the posts on this page first because of the change to system d
let me know if i can help in any way
Jerry
I also have an “Athlon II Dual Core”. Check System Monitor for CPU History. Mine showed around 33 %, also the Firefox process running a YouTube video, showed around 24%.
Thanks everyone for your reply.
@lah7 I haven't checked the BIOS, but I guess I don't really need, because I can feel the cooler speeding up as the temperature raises and the response on the software is very slow and laggy. I don't have any driver enabled neither Compiz for special effects.
@Dave_Barnes HDD is on 50ºC. There's air. I don't know what throttling is. Sometimes I've smelled hot plastic. I'm not exactly sure which one is what. Sorry. 
linuxuser701 Thanks, I'll check on that later.
verndog Right now I'm writing this response with one tab open, Totem is playing a song and that's it. CPU1: 14% CPU2:12%
Open a terminal and type “sensors” and post results here.
You might want to add “CPU Frequency Scaling Monitor” to your top panel. You can then
tell what your CPU throttle is set for. A setting of “Performance” can cause some laptops
to overheat.
sensors
acpitz-virtual-0
Adapter: Virtual device
temp1: +68.0°C (crit = +102.0°C)
temp2: +62.0°C (crit = +102.0°C)
k10temp-pci-00c3
Adapter: PCI adapter
temp1: +73.8°C (high = +70.0°C)
73.8 degrees at 800 MHz? Your heat pipe has leaked all its fluid out and gone bad.
Better check if the cpu fan is connected properly or does it work correctly ! If the fan is under the keyboard just remove the keyboard and start the laptop to see if the fan is really rotating .
Also make sure that all “Air Intakes” aren’t blocked with dust/fluff and that the laptop is on a flat even surface and not on a blanket or other piece of cloth that might cover the fans!. 
Yeah the fan is working and connected and nothing is covering the air intake. So I guessed I’ll have to change the cooler… is there a way to check if it lost all the fluid? Can be refilled?
Hello people 
Looks like Acer Aspire are prone to overheat.
The fluid probably leaked out at the radiator. Those copper fins or vanes are very fragile
and can break the bond between them and the heat pipe and cause leaks if not careful.
I don't know of a way to replace the fluid or repair the heat pipe. The heat pipe
fluid could have been any number of liquids.
The only way to verify that the heat pipe is bad is to stick a temperature
probe into the exhaust port and compare the temperature there with the K10 temperature
listed with the "sensor" command.
BTW, the fan does not necessarily pull any air through the laptop case. Some do but most
do not. Air comes in via the fan port on the bottom and exits through the
radiator. There is no air flowing over the heatsink. An addon laptop cooler
under the laptop may not help much if the heat pipe is bad.
So the best solution is to buy a new one?
I'm doing some more checking. There are a lot of reports of overheating AMD "Caspian" CPUs
not just in Acer laptops. I would hate for you to get a replacement heatsink/cooler only to get no improvement.
I would expect the CPU temp to be less than 60 C at idle.
Temperature limits per Acer:
idle = 55-66
light load = 68-74 (so 73.8 might be OK for lightly loaded, according to Acer.)
moderate load = 78-83
heavy load = 86-91 (so Acer expects 100% loaded to be less than 91 degrees)
Acer Service Manual:
https://drive.google.com/file/d/0B7YW-o6qg2UwUk9JMDFlZlhhVjQ/view?usp=sharing
Lets try this test:
Run some stuff to get the temp up to 85-90 degrees and close everything and let the system idle. How long did it take to heat up from idle temp to 85-90 and how long did it take the fan
to cool it back down to the idle temp? If the cooler is working, the temp should drop rapidly.
You should hear the fan speed up as the temp climbs. I would expect 4000+ rpm to be a really annoying whine.
Your best option might be just to buy a newer laptop. 
This are the temps with no windows open
And it took about 30-35 seconds to go down to those numbers, but in other cases it takes longer because today is kinda chilly. Like 10 or 12 ºC lower than the other days.
How old is the laptop ? Maybe the fan ran out of cooling paste or the processor itself may be out of paste .
I’m not sure how old is the laptop, but might be 4 or 5 years. And like I said before I put some new thermal paste.