2000 Mercury Mystique Owner's Manual - Page 183

Maintenance and care Battery replacement If your original equipment battery requires replacement while under warranty, it will be replaced with a Motorcraft service battery, identical in design technology. Like the original equipment battery, it should not require water addition during its normal life of service; however, for severe service usage or in high temperature climates, refer to the "Scheduled Maintenance Guide" for additional information. Do not overfill the battery cell. If the electrolyte level in your battery gets low, you can add plain tap water to the battery, as long as you do not use hard water (water with a high mineral or alkali content). If possible, however, try to only fill the battery cell with distilled water. If the battery needs water often, have the charging system checked. 183