My car only has 88k miles on it and in May the temperature gauge started to get max hot. Blowing the heat for a while helped but then the gauge would go up again. After reading some forum I took off the radiator cap and let the engine run for a while while slowly adding water. Took it to my mechanic and he couldn't find a problem and only changed the oil.

Flash forward less than 3 months and the same problem is happening again. It doesn't matter what speed I'm going or how long I've been driving the car. At one point when I blasted the heat to cool down the engine the heater stopped working and only cold air would come out with my temperature gauge going into the red zone until I turned off my engine. At one point I wasn't on a road where I could pull off the road and turn off my engine so my needle went to the red on my temperature gauge and then all of a sudden my heat started coming out of the vents and my gauge slowly went down. Again I took it to my mechanic and he can't find anything wrong - he pressurized the system and checked everything and can only surmise that my head gasket is going. With such low mileage I'm perplexed that the head gasket is already going out.
Of course the temperature gauge was always good for him and after having my car back for a few days the temperature gauge started rising again so I had to blast the heat to keep it down. I just let the engine run again without my radiator cap and added a small bottle of water. I don't want to blow my engine with such low mileage. Any ideas? Is it really my head gasket?

 

No mention of replacing the thermostat. Always start with that when there is intermittent overheating, it could be simply the thermostat getting stuck. Be sure to bleed the system fully afterward.