Cooling System: Tools and Equipment

COOLANT CONCENTRATION TESTERS
Description
A hydrometer test will indicate whether ethylene glycol and/or water should be added to maintain the desired freezing point of the solution.

The freezing point of the solution should give protection to an acceptable temperature of -36°C (-33°F), regardless of climatic conditions. This is also necessary to provide adequate corrosion protection.

Some devices used for testing solutions will indicate the correct freezing point only when tested at a specific temperature. Other testers provide thermometers and tables indicating freezing points corresponding to readings made at various temperatures. Disregarding the temperature of the solution when testing may cause an error as large as 15°C (30°F) in determining freezing points.

Operation
Use of a refractometer is recommended especially if the type of coolant is unknown. A J 26568 or J 23688 Coolant Tester (Centigrade and Fahrenheit scale, respectively) can be used to check the antifreeze protection of the coolant. Make sure the refractometer markings are correct. Unless the coolant tester has a provision for temperature correction, test at the temperature for which the tester was calibrated. If the coolant is warmer or cooler, the reading may be incorrect. Follow the manufacturer's directions when using a coolant tester.