A low level of electrolyte fluid will cause the battery to discharge quickly.

Inspect the electrolyte level at least once a week. If it is low, remove the caps and add enough distilled water to bring the level between the upper and lower level (illustration).
Do not overfill.
Examine the specific gravity of the electrolyte with a hydrometer, especially during cold weather. If it is low, recharge the battery.
Battery Maintenance
Battery RechargingMazda 6 Owners Manual: Engine Exhaust (Carbon monoxide)
WARNING
Do not drive your vehicle if you smell exhaust gas inside the vehicle:
Engine exhaust gas is dangerous. This gas contains carbon monoxide (CO), which is
colorless, odorless, and poisonous. When inhaled, it can cause loss of consciousness
and death. If you smell exhaust gas inside the ...
Mazda 6 Owners Manual: Variable valve timing actuator inspection
L3
Caution
Variable valve timing actuator can not be disassembled it is a
precision unit.
1. Disconnect the negative battery cable.
2. Remove the plug hole plate.
3. Remove the high-tension lead.
4. Remove the oil control valve connector.
5. Remove the ventilation hose.
6. Remove the ...