aight this is what exactly happened. the car has been overheating for the last couple of days but it never got to the red mark yet. So i decided to replace the thermostat and still overheated. So yesterday I got home from driving to work and it was overheating and it about the 3.5/4 line on the coolant gauge. It was about 2 or 3 mm off the red. So an hour later I went to the gas station which is about 5 minutes away and when I was driving back the car was getting closer and closer to the red and like two minutes away it got the red and I drove it while in red for about 2 minutes. I came home and nothing was smoking or anything like that so do I just check my oil and see if there any coolant there or what else can I do to make sure the head gasket is ok? thanks alot of the help