FORD 1998 Taurus - Manual (Page 135)

Engine oil and filter recommendations
Look for this
certification mark.
Ford oil specification is WSS-M2C153-G.
Use SAE 5W-30 motor oil certified for gasoline
engines by the American Petroleum Institute.
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 “Service 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,
startup 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.
Maintenance and care
135