The i5-520m came out a very long time ago. let's find a date.
That's over 4 years ago so how did you get such a dated laptop?
And at this age it's a safe bet the heat sink compound is old, dry and cracked. Don't fix that unless you know or have done this work before.
Sony Vaio, model: VPCZ122GX
Owned for a year at most. Constantly cleaning it out with a can of air on a weekly basis. Never dropped or any physical damage, basically in new condition.
Simple things like booting up, sitting idle, or making a windows backup spike to 80C.
Here is a screenshot via speccy. CPU-Z also verified this.
The sensor isn't out because the laptop gets HOT!
Fan is on full speed ahead. All this started two months ago, and I've given up trying to solve this mystery.
Can somebody please help?