Changing ICE Coolant, HV inverter coolant

there are no flushes on the prius, just wallet flushes of their owners.

 

1. The Toyota Super Long Life Coolant should be replaced at 50K mile intervals, after the original factory fill coolant is replaced. So your car actually is a bit past-due.

2. It is not a good idea to use an independent garage that does not characterize itself as a Toyota hybrid specialist. It is too easy to leave air in the engine coolant loop, even some Toyota dealer service techs have done that, based upon PC posts. The inverter coolant loop is fairly easy to drain and replace.

3. If you can replace the iridium spark plugs, you can change the engine and inverter coolant fluids. Ten years ago, I posted on how to correctly change the engine coolant and get air out of the system. See my posts 22 and 42 here:
Changing engine coolant | Page 2 | PriusChat

 

Demand a refund from the Toyota service department. 1) They charged you for a conventional automatic transmission fluid flush that would likely require 8-12quarts of ATF-WS due to the torque converter. 2) The ding-dong tech spilled a f'n quart. He should have used 3.8 quarts MAX!

SURPRISE. The Prius has a TRANSAXLE (think transmission, but NO torque converter). The fluid capacity of the transaxle is just under 4quarts. It is a simple DRAIN and FILL. Just think of the rear center differential on a truck axle; a drain bolt on the bottom, and a fill bolt 90deg on a vertical face. The Prius transaxle has a near identical set-up.

The Toyota Factory Service manual says DRAIN and FILL too!

Earn your manliness badge. Do the coolant drain/fill of both loops (engine & Inverter).

 

I'm not sure why even a conventional automatic would need a flush, basically multiple drain-and-fill. Our daughter's Pilot for example, periodically calls for a transmission fluid change. It states in the Shop Manual that a dry transmission will take about 8.1 liters, and a drain-and-fill will involve only about 3.4 liters. But that's still all it recommends, a single drain-and-fill. The engineers appreciate you're not changing anywhere near all the fluid, but they're ok with periodic replacement of about 40%.

The only time I would recommend a multiple drain-and-fill is in the case of contamination, say you have a brain fart and poured in some motor oil. I believe I've seen that in one of my Honda Shop Manuals. In that case they called for a drain-and-fill, drive it around the block, then repeat, something like two or three times more.