DeVille V8-4.6L VIN 9 (1995)
degree of inaccuracy varies depending on the proportion of other glycols present in the coolant.
All new GM vehicles are produced with coolant that can be accurately measured with a hydrometer; however, when the type and quality of coolant being
measured is unknown, such as a customer vehicle that has accumulated mileage, the use of a refractometer is recommended.
Coolant testers J 26568 (Centigrade Scale) or J 23688 (Fahrenheit Scale) can be used to check the antifreeze protection of the coolant. Make sure the
refractometer markings are correct. Unless J 26568 or J23688 has a provision for temperature correction, test the temperature at which J 26568 or J
23688 is calibrated. If the coolant is warmer or cooler, the reading may be incorrect. Follow the manufacturers' directions on using J 26568 or J 23688.
Clean
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Before each use, swing back the plastic cover at the slanted end of the coolant tester, exposing the measuring window and the bottom of the plastic
cover.
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Wipe the measuring window dry with a tissue or a clean, soft cloth.
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Close the plastic cover.
