Engine warning light came out to take care into a dealer. As I checked the fluids, I noticed that the antifreeze overflow was empty so I filled up the overflow with water and added almost a gallon of water to the radiator. Warning light went off. I watched for leaks but didn't see anything accumulate under the car. Two weeks later, noticed engine was starting to overheat. Refilled radiator and overflow at a gas station (with water)and took the car into a repair show. The initial diagnostic was that there was a leak and it appeared to be coming from the Intake Manifold. Best case scenario I was given - gasket replacement. Worse case - Replace Intake Manifold. However, when they got to the Intake Manifold they realized that wasn't the problem. Now they say it is in the Cylinder and that they believe it is a problem with the head gasket. They quoted me a price of $1100 to 1400 to fix and they said if that is the problem they would send to a machinist to fix. Does this sound right or do you think I being taken advantage of?