Is it critical to change coolant at 100K?

[RMcG]

Originally Posted by tmontague

As i stated above, this will be fine but you will dilute your new coolant below 50/50 due to the water left in it. Make sure you test your coolant's freezing point once you swap it out

Thanks tmontague. I did indeed read your previous post about how you run different dilutions and I am aware that the freezing and boiling points change with dilution. I was more worried, however, about the effect of dilution on the corrosion inhibitors and the lubricants.

I just bought two gallons at the local Toyota dealer, total cost with tax $50 USD. But my worries about corrosion inhibitors and lubricants may be moot, because according to the information on the coolant bottles, the 50/50 freezing point is only -34 degrees Fahrenheit. That is OK where I live now in the Pacific NW of the US, but if I go back to Montana, it is not OK. Because it can get to 40 below in Montana. I will have to call a Toyota dealership back in Montana and ask them what they sell for coolant.

Thanks,

R.