Coolant: Testing and Inspection

Hydrometer
Due to changes in commercially available antifreeze, the use of a hydrometer may give an incorrect reading. The hydrometer should be used to test ethylene glycol base antifreeze only. Ethylene glycol base antifreeze is recommended for year round use.

Coolant Tester
Coolant testers J 26568 (Centigrade Scale) and J 23688 (Fahrenheit Scale) can be used to check the antifreeze protection of the coolant. Make sure the hydrometer markings are correct. Unless J 26568 or J 23688 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 for using J 26568 or J 23688.





Clean
^ Before each use, swing back the plastic cover at the slanted end of the tester, exposing the measuring window and the bottom of the plastic cover.
^ Wipe dry with a tissue or a clean soft cloth.
^ Close the plastic cover.





Testing
Do not remove the clear plastic pump from the tester. Release the tip of the pump from the tester housing and insert the tip into the radiator filler neck. Insert the tip below the level of the coolant.

Press and release the bulb to draw a sample. Bend the plastic tube around and insert the tip into the cover plate opening. Press the bulb and inject a few drops of coolant onto the measuring surface. Do not open the plastic cover when taking the readings because water evaporation can change the reading.





Reading
Point the tester toward any light source and look into the eyepiece.
The antifreeze protection reading is at the point where the dividing line between light and dark (edge of the shadow) crosses the scale the antifreeze protection is the right scale, battery charge is on the left.
The tester temperature scale is reversed from a standard thermometer scale; below zero readings are on upper half of scale. Readings on lower half of scale (above zero readings) indicate solutions without enough antifreeze concentration to provide adequate rust protection.

Tilt the tester toward the light source to obtain the best results. If the "edge of the shadow" is not sharp, the measuring surfaces were not clean or dry. Wipe dry and re-test.