Built-In Hydrometer
A built-in temperature compensation hydrometer is molded into the top of the maintenance free battery. When observing the hydrometer, make sure the battery top is clean. Use a light in poorly-lit areas.Under normal operating conditions, one of three indications can be observed:
1. Any green appearance in the hydrometer is interpreted as a green dot. This means the battery is ready for testing.
2. A dark dot is visible. If the green dot is not visible and there is a complaint about cranking, refer to Charging System Check or Battery Electrical Drain/Parasitic Load. Testing and Inspection Testing and Inspection
3. A clear or light yellow dot means the electrolyte level is below the bottom of the hydrometer and is too low for diagnosis. The yellow dot may have been caused by the following conditions:
^ Excessive or prolonged charging
^ A broken case
^ Excessive tipping
4. When you find a battery in this condition, this may indicate high charging voltages caused by a faulty charging system. Because of this, the charging and electrical systems must be checked.
5. If the battery has a yellow or clear hydrometer, replace the battery if a cranking complaint exists.