You could simply refix the hose but it begs the question, why did it become detached in the first place? If the cooling system is becoming over-pressurised then the car could be overheating (faulty thermostat? faulty water pump? leaking head gasket?).
If you do refix the hose and it blows off again, I'm with the garage on this one. Would appear to require further investigation.
ChicksFan
December 2009
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