Ford 2005 Grand Marquis Owner's Manual page 183

Driving
DRIVING THROUGH WATER
Do not drive quickly through standing water, especially if the depth is
unknown. Traction or brake capability may be limited and if the ignition
system gets wet, your engine may stall. Water may also enter your
engine's air intake and severely damage your engine.
If driving through deep or standing water is unavoidable, proceed very
slowly. Never drive through water that is higher than the bottom of the
hubs (for trucks) or the bottom of the wheel rims (for cars).
Once through the water, always try the brakes. Wet brakes do not stop
the vehicle as effectively as dry brakes. Drying can be improved by
moving your vehicle slowly while applying light pressure on the brake
pedal.
Driving through deep water where the transmission vent tube is
submerged may allow water into the transmission and cause
internal transmission damage. Have the fluid checked and, if
water is found, replace the fluid.
183
2005 Crown Victoria (cro)
Owners Guide (post-2002-fmt)
USA (fus)