Coolant Tester Accuracy

[Mayhem_J30]

How accurate are these things? I purchased on for only $12 at an autozone. Looks like they are based on bouyancy to test boiling/freezing points. I purchased one because a very short time ago I flushed the coolant and refilled with distilled water and Prestone. Now the Valvoline IOC said there's to much water in there and it may freeze. The device they used looked a lot like what I purchased. After using what I purchased myself the freezing point surpassed -34F!! That should be plenty right?If the tester was a waste of money, that's fine, $12 would have been worth my time if I don't have to replace the coolant again.

[autotech43]

A quick way to check any anti-freeze tester is to get you a mixture of 50% anti-freeze and 50% water. Mix the two together. Look on the side of the coolant bottle and see the freeze protection when the mixture is at the 50/50 ratio. Draw the mixture into your tester and compare the result of your actual reading as to what it is supposed to be. You can even do a calibration to your tester if it is off a bit. Nissan/Infiniti have a long life antifreeze/coolant which gives you a freeze protection of 34 degrees below zero and a boiling protection to 265 degrees when at the 50/50 mix.:peace

[Q45tech]

"a boiling protection to 265 degrees when at the 50/50 mix."ASSUMING you can obtain a 14.7 psi pressure but Nissan caps are designed for [to let go at] 0.9 BAR so 255 F would be a better assumption!!!!!!!!!!