The exact answer to this question really depends on the specific car, the temperature, and various other factors. Generally, it can take anywhere from a couple of minutes to a few hours for an engine to suffer a catastrophic failure, depending on how hot the engine gets and how long it has been running at that temperature. Damage can also occur even if the engine doesn’t overheat if the cooling system is failing and not providing enough cooling for the engine. In other words, overall engine health and performance should be monitored closely and any signs of overheating should be addressed immediately, as serious damage can occur in as little as a few minutes once an engine starts to overheat.
