Opinions on engines lasting so long with broken cooling systems?

[trademe900]

Currently the planes last so long with broken cooling systems as it takes forever before the oil temperature starts to rise even the slightest bit.

It is my opinion that high powered aircraft engines that are at full throttle for so much of the time are going to boil their oil very quickly with a pressurized coolant system that has been smashed by bullets.

I see so many planes with coolant gushing from them still challenging for fights like there's no tomorrow.