Generally when a water pump goes it starts to leak, it may be the water pump or just a hose or conection. If its warm enough out take the vehicle to the car wash and spray where it is wet. This will clean the old fluid off you should be able to see in what area it is leaking keep checking for the leak. Did you change the thermastat to? The circulating system may be vapor locked. To check if the thermastat is working. Start car let run until you can feel when the thermastat opens by feeling the top hose. When it starts to heat up you can feel the antifreeze ciculating. At that time go in and check your temp guage. When you loose antifreeze the first hing happens is there is no heat.