Diagnosis And Testing - Coolant Concentration Testing

Check coolant concentration when any additional coolant is added to the system, or after a coolant drain, flush and refill. Use of a hydrometer or the Refractometer 8286 can be used to test coolant concentration.

• A hydrometer tests the amount of glycol in a mixture by measuring the specific gravity of the mixture. The higher the concentration of ethylene glycol, the larger the number of balls that will float, and the higher the freeze protection (up to a maximum of 60% by volume glycol).
• The Refractometer 8286 tests the amount of glycol in a coolant mixture by measuring the amount a beam of light bends as it passes through the fluid. Refer to SPECIAL TOOLS .
• Some coolant manufacturers use other types of glycols in their coolant formulations. Propylene glycol is the most common new coolant. However, propylene glycol based coolants do not provide the same freezing protection and corrosion protection and are not recommended.

Fig 1: Using Refractometer To Test Coolant

Courtesy of CHRYSLER GROUP, LLC

1. Visually inspect the coolant for contamination. Must be free of oil, dirt and/or other materials that can adversely affect the cooling system.
   • If the coolant is found to be contaminated  after a visual inspection, discard the coolant.
   • If the coolant is found to be clear of contamination  after a visual inspection the test the coolant concentration.
2. Using a Refractometer 8286 or equivalent, following the manufacturer's instructions, test the coolant freeze point:
   • If the coolant freeze point is between  -31°C and -45°C (-25°F and -50°F), save the coolant for reuse.
   • If the coolant freeze point is not between  -31°C and -45°C (-25°F and -50°F), discard the coolant.