Are you overheating? we need to know where the exact leak at-picture of it would be great, if there's no external leak-its possible that it's burning in the combustion chamber-do you see any white smoke after the engine comes up to operating temperature coming out of the tail pipe and also check the oil if its milky colored and wet floorboard which is a sign of heater core leaking-let check all this things and get back with me asap if further assistance needed