i pretty much had both go on my car at the same time...my car would leak and generally lose alot of coolant/water and i'd have to refill almost daily and sometimes more often depending on how much driving, etc

i still had heat from my heater

is your car leaking coolant from towards the right side??? ..if so definitely the waterpump if not leaking it still may be the pump but it might just be the thermostat

i had mine fixed at mis-dealer while getting the atx replaced...my warranty paid for the pump, but not the thermostat...fair trade off for me

99 expedition eddie bauer, 5.4 v8, k&n drop-in, 3" magnaflow catback and gas mileage that makes the contour look like a hybrid