answer:My first guess would be the coolant. If your low coolant light is not coming on it is possible that the bulb is burned out. Another possibility is a stuck thermostat. There is a little valve that controls how the coolant circulates through the engine. When cold the valve is closed so that the engine can heat up, then it opens to circulate the coolant to keep the engine cool. This valve or the thermostat that controls it can go bad and keep the coolant from circulating properly. You could have a bad fan clutch or damaged fan.