I am seeing the same issue here… Here is my setup
I have got 4 rasp pi3 they are all running osmc, but one of them is running 18.x latest alpha version. On that modul I can see that the temp is going way above 82 degrees. But on my 3 other there is running 17.4 version their temp is only around 60-70 degrees.
can this be caused by a license issue or??
I moved your post to a new thread as the other one was already quite old and you are using a testing version of Kodi.
I suggest you better describe what you are doing when the temperature increase or is the temperature high when the device is idle?
Just to add to what @fzinken said, the Pi 3 is known to run quite hot and will certainly benefit from a stick-on heat sink, which will probably shave 10 degrees or so from the running temperature. Also the amount of ventilation through the enclosure can make a noticeable difference. If you’re already running with a heat sink, then 60-70 degrees seems a bit high for Kodi 17.4, though, as mentioned already, it depends what you’re doing (eg HEVC will really push the CPU). At idle, I’m getting around 50 degrees with a heatsink and reasonably well ventilated enclosure - it’s the RS enclosure - and down to 40 degrees when Kodi is disabled.
If you run the top command (or htop) you should get a better idea if anything is burning up the CPU. Press 1 to toggle between per-CPU and total-CPU figures.
I see the high temp when I am watching a HD channel on my tvheadend client.
top command before I start my tvheadend client
osmc@OfficeTV:~$ top
top - 20:59:19 up 8:28, 1 user, load average: 0.90, 0.52, 0.47
Tasks: 128 total, 1 running, 127 sleeping, 0 stopped, 0 zombie
%Cpu(s): 6.9 us, 0.3 sy, 1.0 ni, 91.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 749584 total, 447548 used, 302036 free, 72148 buffers
KiB Swap: 0 total, 0 used, 0 free. 135240 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
598 osmc 20 0 799876 242340 48124 S 32.0 32.3 216:06.68 kodi.bin
32422 osmc 20 0 3212 1836 1388 R 0.7 0.2 0:00.24 top
And temp before:
GPU => temp=62.3’C
CPU => 62’C
osmc@OfficeTV:~$
top after 5min:
top - 21:08:36 up 8:37, 1 user, load average: 0.30, 0.42, 0.45
Tasks: 127 total, 1 running, 126 sleeping, 0 stopped, 0 zombie
%Cpu(s): 7.7 us, 0.5 sy, 2.4 ni, 89.0 id, 0.3 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 749584 total, 469956 used, 279628 free, 72548 buffers
KiB Swap: 0 total, 0 used, 0 free. 139312 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
598 osmc 20 0 875692 260924 49196 S 11.9 34.8 218:50.31 kodi.bin
844 osmc 20 0 3240 1820 1392 R 5.9 0.2 0:00.03 top
And temp
GPU => temp=79.5’C
CPU => 78’C
osmc@OfficeTV:~$
And the temp will only keep raising…
i am running with heat sink on all my rasp pi3. 
And ventilation?
standard case for a rasp, so no special vent here… but on my 3 other rasp where I am running version 17 I am not having the issue
After 15 min the temp is now
GPU => temp=81.7’C
CPU => 81’C
I think this is one for the Raspberry Pi and/or Kodi gurus.
It doesn’t look to be the CPU that’s the issue here so I’m guessing it’s most likely to be something to do with the GPU’s interaction with Kodi 18.
When you’re on the bleeding edge, this kind of thing is going to happen.