I put 0.5 litre of washer liquid in the pink engine coolant tank

[Hstrong]

Help will I have done much damage to a 2016 Prius by topping up pink engine coolant reservoir with window washer liquid ?

[FROSTYBALLS]

Moved to the Prius club

[Mooly]

Best advice would be to get the system thoroughly flushed and then refilled with the correct antifreeze as soon as possible.

In the short term it almost certainly OK but I would not drive it beyond taking it to have the system flushed. Leaving the stuff in there could be asking for trouble in the long term as you just don't know how the two liquids will chemically react over time. 0.5 Litre is a big percentage of the total coolant capacity. 

[wass]

My sympathies . Have you run the engine since? If not, syphon the stuff out. If you have run the engine, flush the entire system as previously recommended. Look on the bright side, it will have done less damage than putting windscreen washer fluid into the brake fluid or the engine oil. Every cloud has a silver lining, of all the fluid mistakes to make , you chose one of the least damage options. I suppose it could be argued that one the very least damaging options would be to put tap water in the coolant instead of the windscreen washer bottle. (modern vehicles really dont do well on just plain old water anymore but water will get you home in either coolant or windscreen washer bottle.)

[kithmo]

Good advice above, siphon it out, or drain and flush the system if it's circulated. Washer fluid contains Methanol which attacks some plastics and rubber (hoses etc) and could be corrosive to engine components.