Ford Windstar Owner's Manual page 297

While the engine idles, turn the steering wheel back and
2.
forth several times. Make sure that the cap assembly is
installed at this time.
Then turn the engine off.
3.
Check the fluid level in the power steering fluid reservoir.
4.
The power steering fluid cap
If the power steering fluid is low, add fluid in small
5.
amounts, continuously checking the level, until the fluid is
between the minimum (MIN) and maximum (MAX) lines on
the dipstick. Do not overfill.
Make sure the cap is free of all dirt prior to re-installing to
6.
prevent pump damage.
Use only power steering fluid that meets Ford Specification
ESW-M2C33-F, such as Ford Premium Power Steering Fluid,
E6AZ-19582-AA or an equivalent Type F Automatic Transaxle
Fluid with a Ford registration number (an 8-digit number
beginning with "2P" printed on the fluid container).
Maintenance and Care
297