I have a MacBook (oldish late 2012 retina 13") that seems to exhibit classic overheating symptoms, except that it isn't hot.
Under load it tends to shut down after a while, can be turned back on after a few minutes, and can be "fixed" by using iStat Menus to force the fans to always run. (Of course iStat Menus couldn't help during OS upgrade, so to be able to finish that, I had to put the MacBook in the fridge -- that worked.)
However, it's barely lukewarm to the touch, and according to iStat Menus, none of its temperature readings are high. But when CPU Die temp goes above 70C (CPU Proximity ~55C), it shuts down. I think that should only happen somewhere above 100C, correct? Without the iStat Menus override the fans wouldn't even start running yet when it shuts down.
I've already tried SMC reset, PRAM/NVRAM reset, and fully reinstalling macOS; none of these helped. Any further ideas for how I could fix it?