The engine/coolant light came on in car, and I took it to garage which was filled with the fluid. Approximately 2 months later, the light is flashing on and off at times, but not staying on. The engine does not sound normal when started, or when turning off. I looked at the reservoir, and it seems that the engine/coolant is running low again like there may be a leak somewhere. What would cause this? Could it be as simple as hoses, or something with the engine?