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: General procedures
PRECAUTION (CLUTCH)
Clutch Pipe Removal/Installation
Note
A common reservoir is used for the clutch and brake system fluid.
1. If clutch pipes have been disconnected any time during the procedure, add
clutch fluid (brake fluid), bleed the air, and inspect for leakage after the
procedure ...
Mazda 6 Owners Manual: Operating Tips for CD Player
Condensation phenomenon
Immediately after turning on the heater when the vehicle is cold, the CD or optical
components (prism and lens) in the CD player may become clouded with condensation.
At this time, the CD will eject immediately when placed in the unit. A clouded CD
can be corrected sim ...