Does replacing water pump also replace coolant?

From what I read on PriusChat, most inverter pumps were changed under warranty without changing the coolant, so you should assume that the inverter loop has never been changed. One gallon of coolant is not enough to change the engine loop, so you should assume that it was never completely changed, even if they used the full gallon.

The maintenance schedule for Gen 2 calls for the initial change of the coolant at 100K, and subsequent changes at 50K intervals. Since it has been 50K since your last change, both of the systems in your car are due for a change now, even if they were changed when the work was done.

The logic behind the schedule is that you really can't get all of the old coolant out of the system when you change it. The old coolant that remains in the system reduces the change interval.

 

I agree with Robert's statements. Furthermore, others on PC suggest to consider installing another new inverter coolant pump at the coolant change interval as well for additional piece of mind. And while its not necessarily recommended by Toyota nor your dealer (you can guess why) at100K miles would be a good time change your transaxle fluid as well if it hasn't been done recently.