4.11 - Engine: Overheat!

[JtD]

That's true, the overheat message comes on as soon as there is a chance to damage the engine. A little bit of overheat however has a very small chance to damage the engine at all.

If you fly full power / max. pitch with radiator open in high speed level flight, you can probably fly for a long time before anything happens.

You shouldn't sit on the runway having the engine maxed out, it's going to blow fairly quickly.