Grand Cherokee 2WD V6-3.7L (2008)
Coolant: Testing and Inspection
COOLANT CONCENTRATION TESTING
Coolant concentration should be checked when any additional coolant was added to system or after a coolant drain, flush and refill. The coolant mixture
offers optimum engine cooling and protection against corrosion when mixed to a freeze point of -37°C (-34°F) to -46°C (-50°F). The a hydrometer or a
refractometer can be used to test coolant concentration.
A hydrometer will test 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 higher the freeze protection (up to a maximum of 60% by volume glycol).
A refractometer, Tool 8286 See: Tools and Equipment will test the amount of glycol in a coolant mixture by measuring the amount a beam of light bends
as it passes through the fluid.
Some coolant manufactures use other types of glycols into 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 is not recommended.
CAUTION: Do not mix types of coolant - corrosion protection will be severely reduced.