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: Oil cooler removal/installation
1. Disconnect the negative battery cable.
2. Drain the ATF into a container. (See AUTOMATIC TRANSAXLE FLUID (ATF)
REPLACEMENT.)
3. Remove the radiator. (See RADIATOR REMOVAL/INSTALLATION.)
4. Remove in the order indicated in the table.
5. Install in the reverse order of removal.
6. Add ATF to ...
Mazda 6 Owners Manual: Air bleeding
Caution
Maintain the fluid level in the reservoir tank properly while
bleeding the air.
Specified fluid
Note
The brakes should be bled whenever a brake line is disconnected.
If a hydraulic line is disconnected at the master cylinder, start at the
slave cylinder farthest from t ...