Hello and welcome to Just answer.com, Super mechanic here. Please DON’T hit accept until you are completely satisfied with the answer. If you need any more on it just let me know. About your vehicle.
Hard to say for sure without seeing the car but from the location I would have to say that it sounds like the auxilary coolant pump. They can leak intermitently and at different temperatures as well. You would want to have the system pressure tested to be 100% sure though and most any reputable, (certified) repair shop could do that as well as replace it if that IS the leak.
WATER AUXILIARY PUMP LH front of the engine compartment, to the right of the battery