pH of some coolants

Snagglefoot

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Keep the samples a few days and retest. Rinse the meter between readings with water.
So here we are, five days later, starting at 8.08 with the mixed Prestone Cor-guard sample, the pH is 8.06, essentially the same.

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This is all interesting, but what is important is that the chemistry of the coolant is such that it maintains that slightly basic pH (power of Hydrogen) for a period of time without having to start out as highly basic. This is that others meant when using the term "buffered". It would be just as bad to be highly basic as it is to be highly acidic.

A more meaningful test would be to put that coolant into use and measure the pH over time to see how long it takes for the coolant to reach a damaging level of acid pH.
 

Snagglefoot

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Ok. Let’s open this up for pH numbers for actual coolants in service.
I’ll go first. 05 Ford Taurus. Two year old Prestone with Core Guard with what might be 60 % coolant mixed with distilled water. One pic of it in the antifreeze tester ( around -45 F). The pH is 7.94.

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