Ford Grand Marquis Owner's Manual page 222

4. Check the fluid level in the power steering
fluid reservoir. The fluid level should be
between the MIN and MAX lines on the side
of the reservoir.
5. If the power steering fluid is below the MIN
mark, add fluid in small amounts until the
level is between the MIN and MAX lines on
the side of the reservoir.
6. When you are finished, put the cap assembly
back on the reservoir.
Fluid level for power steering
Use only power steering fluid that meets Ford
Specification Mercon ATF XT-2-QDX or an
equivalent.
If the power steering fluid is low, do not drive
your vehicle for a long period of time before
adding fluid. This can damage the power
steering pump.
223