Use coolant testers J 26568 or J 23688 in order to check the antifreeze protection of the coolant. The markings of the refractometer must be correct. Unless J 23688 or J 26568 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 manufacturer's directions on using J 26568 or J 23688 .

Tools Required

Important: 

•	Before each use, lift up the plastic cover at the slanted end of the J 23688 or J 26568 exposing the measuring window and the bottom of the plastic cover.

•	Wipe the measuring window with a tissue or a clean, soft cloth.

•	Close the plastic cover.

1. Release the tip of the pump from the coolant tester housing. J 23688 or the J 26568
2. Do not remove the clear plastic pump from the J 23688 or the J 26568 .



3. Insert the tip of the pump into the surge tank. The tip of the pump must be below the level of the coolant.
4. Press the bulb. Release the pump bulb in order to obtain a sample of the coolant.
5. Insert the tip of the pump into the cover plate opening.
6. Press the pump bulb. Allow a few drops to fall onto the measuring surface. Do not open the plastic cover when taking readings because any water evaporation can change the reading.



7. Point the coolant concentration tester toward any light source. Look into the eyepiece.

•	The coolant protection reading is at the point where the dividing line between light and dark crosses the scale. Antifreeze protection is the scale on the right.

•	The temperature scale is reversed from a standard thermometer scale.

•	Below zero readings are on the upper half of the scale.




8. If the readings are not clear, properly clean and dry the measuring surface. Conduct a new test.