19
I think blowing up your mech is almost always a bad idea. It worked out VERY well once. And only once as far as I can tell and in that circumstances you had:
1: an entire enemy force in a deep canyon that had been mined with bombs that just needed one explosion to set off.
2: the only allie force was a single mech.
3: That mech had a second person in the cockpit to pull out the relevant circuits at the exact right moment becuase they were not located for easy mid-combat access.
In that one very specific circumstance it was the right choice. Under almost all other circumstances it is just a bad idea. MAYBE if you are engaged in melee against a single target who REALLY needs to die for greater reasons than meerly tactical, and you don't value your own life much. Even then there are probably better ways to go about it like just ignoring the heat scale and letting nature take its course.