Well - the initial coolant change interval is at 100K miles. I think it would be reasonable to change the inverter coolant pump at that time (assuming it did not already fail.) Subsequent coolant change intervals are at 50K miles. That's probably too soon as a pump replacement interval. Its not clear whether current production 2G inverter coolant pumps are better or worse than older pumps.
your Prius will detect an overheated Inverter and protect itself. I replaced my Inverter coolant pump (electric) and the ICE water pump at 150,000 miles. The replacement electric Inverter coolant pump is an improved design so it promises to last longer than the ones in a 2004 or 2005 Prius. I just do drain and refills, not flushes. JeffD
