GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 26568 Coolant Tester (Centigrade)
    • J 23688 Coolant Tester (Fahrenheit)

Inspect the coolant for freeze protection and contamination.

The following fluids may cause contamination:

    • Engine oil
    • Automatic transmission fluid, if equipped

Inspect the following qualities of the coolant in order to detect contamination:

    • The color
    • The smell
    • The feel

Diagnose and repair the cause of the contamination in order to prevent engine damage.

Use the J 26568 or the J 23688 in order to inspect the antifreeze protection of the coolant.

Ensure that the hydrometer markings are correct.

Unless the J 26568 or the J 23688 has a provision for temperature correction, test the temperature at which the J 26568 or the J 23688 calibrates. If the coolant is warmer or cooler, the reading may be incorrect.

Follow the manufacturer's directions for using the J 26568 or the J 23688 .


Object Number: 13709  Size: SH

Object Number: 13713  Size: SH

Important: 

   • Do not open the plastic cover when taking the readings.
        The coolant may evaporate. The evaporation may change the readings.
   • If the readings are unclear, determine if the measuring surfaces were cleaned and dried.
         Wipe the measuring surfaces dry. Repeat the test.

Use the following procedure in order to clean the coolant tester:

  1. Before each use, swing the plastic cover at the end of J 26568 or J 23688 in order to expose the measuring window at the bottom of the plastic cover.

  2. Object Number: 13712  Size: SH
  3. Wipe the measuring window dry with a tissue or a clean soft cloth.
  4. Close the plastic cover.