!00K on the car, and dealer charges $375 for flushing, and refilling both cooling systems. Seems expensive to me. Has anyone done this themselves?
Our Own @NutzAboutBolts has videos. I haven't done this myself (company car) but it seems fairly straight forward.
An actual "flush" is not necessary. But it takes maybe an additional 10 minutes for them and adds maybe $100 to the price. Ask them about just a drain and refill. The price should be considerably less.
In my opinion flushing is a waste and not necessary for your Prius. I changed mine myself at home for both the engine(ICE) and the inverter. Purchasing the Toyota Super Long Life Coolant on Amazon was easiest for me. There is a drain plug on the radiator and the block for the ICE coolant. Drain plug on the transmission for the inverter, it takes a large metric allen head. Capture what you drain out and put the same amount back in. I had no problems with bubbles, vapor lock or anything like that. If you can get in what you took out then you are done. Otherwise if you don't have the space to tech then do as earlier poster said and just ask for a drain and refill, flushing just flushes out your wallet.
I think "flush" is just a commonly used term. @NutzAboutBolts calls it flush, but is doing drain-and-fill. With only 50/50 mix fill readily available, doing a straight water flush would make it difficult to achieve proper mix afterwards. And: where would all the flush water being going? Down the street to the nearest storm drain? It's just an old-school term, still in use, but reality is a drain/fill. Kinda like hub caps: used to mean caps on the hubs, now often used to describe wheel covers.