My 3-year-old Peugeot 307 1.6 semi-automatic last week had its thermostat housing replaced after losing huge amounts of water overnight. My local garage has told me that the car is showing early signs of head gasket failure. The car has only done 22,000 miles and has just come out of its warranty. Am I driving a heap of potential trouble? Do I get a second opinion? Other than water leaks and overheating should I be looking out for any other signs that indicate head gasket failure?