2003 Ford Mustang Owner Guide 5th Printing - Page 164

Maintenance and Specifications unnecessary and could lead to engine damage that is not covered by Ford warranty. Change your engine oil according to the appropriate schedule listed in the scheduled maintenance guide. Ford production and aftermarket (Motorcraft) oil filters are designed for added engine protection and long life. If a replacement oil filter is used that does not meet Ford material and design specifications, start-up engine noises or knock may be experienced. It is recommended you use the appropriate Motorcraft oil filter (or another brand meeting Ford specifications) for your engine application. BATTERY Your vehicle is equipped with a Motorcraft maintenance-free battery which normally does not require additional water during its life of service. However, for severe usage or in high temperature climates, check the battery electrolyte level. Refer to the scheduled maintenance guide for the service interval schedules. Keep the electrolyte level in each cell up to the "level indicator". Do not overfill the battery cells. If the electrolyte level in the battery is 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 cells with distilled water. If the battery needs water often, have the charging system checked. If your battery has a cover/shield, make sure it is reinstalled after the battery has been cleaned or replaced. 164 2003 Mustang (mus) Owners Guide (post-2002-fmt) USA English (fus)