MichaelTM

maybe there's no damage at all...

but otherwise - damn!

Audiboy

to overheat, thus creating so much pressure and blew a radiator hose.

MichaelTM

expansion tank would be steaming long before that, wouldn't it?

Audiboy

unknowingly by driver, super heated steam by an engine over 150C creates so much pressure that the little hole on the radiator cap (releasing at around 1 bar pressure) cannot release enough steam pressure volume. The next weakest link is the radiator hose because of it's size in diameter and the force exerted by the pressure on that large area. The pressure is so great it moves locomotives

I've seen many blown radiator hoses with fully functional radiator caps. Most of the radiator hoses are blown because of bad head to block sealing though (head gaskets).

German cars on the other hand are very finicky when it comes to cooling. The hardest cars I've worked with making sure the system is properly bled is the VW Vanagon (rear engine, front radiator) and the water cooled Porsche's. The A4/S4 V6 engines have special bleed ports to make sure there is no air trapped in the system