Druzzic. You are thinking that the sensor can see everything. It can't. The phenomenon is called hotspots. Think of a grid 15x10. That's just 150 little squares. The sensor is a thermal strip, like a piece of tape, that travels down the middle of that grid lengthwise. If your temp reads 36°,thats the generalized temp of that entire grid. If you have an air bubble above 3 of those little squares, that's a Hotspot. That temp can reach well over 200° (silicon melts much sooner) in a matter of seconds, of which the core will still read 36°. That hotspot would have to be right on top of the sensor for you to even see a temp difference, and since 12 of the squares read 36, it'll get averaged with the 3 hot squares, so you'd see a core temp of @68° which would only last a few seconds before the transistors burned out and the core goes back to 36. That's assuming it didn't burn out the sensor. In the meantime, you now have transistors burned out (kinda like bad sectors on a hdd) and mostly the core works just fine. But every now and then, that core will deal with a large bandwidth file or be using 2x files simultaneously using up space, and that data will get caught in those bad sectors and create an error. Sometimes that'll show as a freeze, sometimes if the data was important it'll hit as a bluescreen and you'll get irq=less than zero errors or ntkernal errors etc.
Picture it this way. Go wax the hood of a car, but leave out 1 little spot. After you are done, you can't see the spot you missed. No one can tell the difference. Sunny, cloudy, nice weather, you'll never tell. Until it rains and the water beads up everywhere except that 1 little spot that is now totally visible. That's what happens with the pc. It never sees the damage. You can't see the damage. There's no way to see it at all until you get the right combination of circumstances, and then whammo! The pc freezes.