Is it OK to use 60% coolant/40% distilled? I didn't buy enough of either .

Thinking if I used half the next jug of coolant to make 60/40, I could save it for the next change and do the same thing.

 

It probably won't do any harm but water has a higher heat capacity than glycol. That means you'll get less heat transfer and cooling than you would with more water. Shouldn't be a big problem this time of year but it might be in the summer.
The freezing point will be lower with 60/40, but I don't thnk you have to worry about -40 or -50 in AZ.

 

[HIJACK]
Your avatar....Paintball mask???
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Yes it is! Now you can win the prize if you can name what brand it is .


I opened up the top vent instead of turning on the heat when draining the rad Oh well, at least 90% is fresh coolant.

 

I've heard that you shouldn't go over 68% coolant.

 

You will have very very poor heat disipation capabilities. While coolant provides a higher boiling point and lower freezing point it holds the heat longer. The general rule of thub is 50/50, and if you live in an area that doesnt get too cold I would run 40coolant/60distilled... it will take less time for your coolant to cool, thou toyotas generally dont have issues cooling....