Ford 1996 Thunderbird Manual page 249

Battery
Your vehicle may have a Motorcraft
maintenance-free battery. When the original
equipment battery is replaced under warranty, it
may be replaced by a Motorcraft
Low-Maintenance Battery.
The Low-Maintenance Battery has removable
vent caps for checking the electrolyte level and
for adding water, if necessary. The electrolyte
level should be checked at least every 24 months
or 24,000 miles (40,000 km) in temperatures up
to 90˚F (32˚C) and more often in temperatures
above 90˚F (32˚C). Keep the electrolyte level in
each cell up to the level indicator. Do not
overfill.
If the level gets low, you can add tap water to
the battery, provided the water isn't hard or
doesn't have a high mineral or alkali content.
However, if possible you should refill the battery
with distilled water. If the battery needs water
quite often, have the charging system checked
for a possible malfunction.
Help Us Protect Our Environment
Ford Motor Company strongly recommends that
used lead-acid batteries be returned to an
authorized recycling facility for disposal.
Battery recycling symbol
Because your vehicle's engine is electronically
controlled by a computer, some control
conditions are maintained by power from the
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