Just now I opened the bonnet of a ~8? yr old Avalon to top up the windshield washer reservoir.

As I now know :) idiotically the coolant top-up reservoir and the windshield washer reservoir are right next to each other and look the same!

I put only about a cup of the blue windshield wash in the coolant top-up reservoir.

The coolant top-up reservoir was otherwise, almost full with the usual "pink colored" coolant stuff.

The vehicle is running perfectly, as-new, is perfectly maintained, and never "uses" any coolant even on long runs. (I've never seen the level drop in the coolant top-up reservoir.)

Any thoughts on this?

1 Answer 1


If you have not operated the engine to temperature since the mishap, you can siphon out the not-so-contaminated liquid in the reservoir and replace it with the correct mixture of coolant. It's only when the engine reaches temperature and then cools that the reservoir will pull any "overflow" from the tank, or will fill any reduction from use.

If you have noted the level in the not-so-contaminated tank but have operated the vehicle to temperature and the level has not changed appreciably, there is a strong possibility that there's been no transfer.

Considering that water makes up at least fifty percent of your coolant and water comprises more than fifty percent of the windscreen washing fluid, even a one-hundred percent transfer would mean very little of the mixture would become coolant.

Your last declarative sentence bodes well for your situation.

  • Sorry I forgot to "tick" this! Cheers
    – Fattie
    Dec 1, 2022 at 15:09

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