1996 Mercury Grand Marquis Owner's Manual - Page 257

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 255