Lumina V6-3.8L VIN K (1998)
Coolant: Testing and Inspection
Coolant Concentration Testing
Due to a worldwide shortage of Ethylene Glycol, some coolant manufacturers have started to mix other types of glycol into their coolant formulations.
Propylene glycol is the most common new ingredient. A hydrometer will not always provide a correct measurement of freeze protection when
anything other than ethylene glycol and water is being tested. The degree of inaccuracy will vary depending on the proportion other glycols present in
the coolant.
All GM vehicles are produced with coolant you can accurately measure with a hydrometer. However, when the type and quality of the coolant being
measured is unknown, such as a vehicle that has accumulated mileage, use a refractometer.
Use coolant testers J26568 or J23688 to check the antifreeze protection of the coolant. The markings of the refractometer must be correct. Unless
J23688 or J26568 has a provision for temperature correction, test the temperature at which J26568 or J23688 is calibrated. If the coolant is warmer or
cooler, the reading may be incorrect. Follow the manufacturer's directions on using J26568 or J23688.
TESTING PROCEDURE
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Tools Required
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J23688 Coolant Tester (Fahrenheit Scale)
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J26568 Coolant Tester (Centigrade Scale)
IMPORTANT:
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Both J23688 and J26568 automatically compensate for temperature.
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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.
1. Release the tip of the pump from the housing of the J23688 or the J26568.
2. Do not remove the clear plastic pump from the J23688 or the J26568.
CAUTION: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the
solution in the radiator without causing the solution to boil. removal of the radiator cap while the engine is hot and pressure is high will cause the
solution to boil instantaneously-possibly with explosive force-spewing the solution over the engine, fenders and the person removing the cap.
Under some conditions, the ethylene glycol in the engine coolant is combustible.
3. Remove the surge tank/radiator cap.
4. Insert the tip of the pump into the surge tank/radiator. The tip of the pump must be below the level of the coolant.
5. Press the bulb. Release the pump inch lbs. order to obtain a sample of the coolant.
6. Bend the tube around the J23688 or the J26568. Insert the tip of the pump into the cover plate opening.
7. 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 will change the reading.
