Hi all.. I own a 2006 Mazda3. Recently, I have noticed that the engine is overheating. I have shown it with a car care center Service Plus in Toronto and they said that the coolant level is low and there is coolant leakage too. The issue is with head gasket and they suggested to replace it. Does any one here ever experienced such a problem? How does the coolant leakage occur? How we have to care for this?