help! car hose blown

[jlee]

Could do with some urgent advice. I was driving to work earlier on and the warning lights started to flash on the car, the sat nav was flashing on/off. Ive had this before and it normally goes if you turn the car off and on again. Few seconds later I heard a bang and loads of steam is coming out the bonnet. Looked under and all the water has come out and the large hose has blown off by the radiator at the top. Any idea's why this would happen? Is it pressure building up or just a dodgy hose? I am waiting for the AA to come out in a bit. I'm hoping they can repair the hose and refill it or least get me to a garage. Car is 645 4.4 with N62 engine.

Thanks

[Higgs boson]

The two issues may not be related.
Obviously, the cooling system is pressurized. Had the hose been off/replaced recently?
It's easy to not locate them properly due to the design - they appear to be in position, the clip will push on, but not actually hold the hose in place once the pressure builds up.
If your model has an electrically operated thermostat (I don't know if it does), it's possible that it has failed to open when required, and that the extra pressure has blown the hose off.