FORD 2003 Mustang v.3 - Manual (Page 164)

Do not use supplemental engine oil additives, oil
treatments or engine treatments. They are
unnecessary and could, under certain conditions,
lead to engine damage which is not covered by your
warranty.
Change your engine oil and filter 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.
Maintenance and Specifications
164