Mercury 2009 Grand Marquis Owner's Manual page 193

Tire change procedure
WARNING: When one of the front wheels is off the ground, the
transmission alone will not prevent the vehicle from moving or
slipping off the jack, even if the vehicle is in P (Park).
WARNING: To help prevent the vehicle from moving when you
change a tire, be sure the parking brake is set, then block (in
both directions) the wheel that is diagonally opposite (other side and
end of the vehicle) to the tire being changed.
WARNING: If the vehicle slips off the jack, you or someone else
could be seriously injured.
WARNING: Do not attempt to change a tire on the side of the
vehicle close to moving traffic. Pull far enough off the road to
avoid the danger of being hit when operating the jack or changing the
wheel.
1. Block the diagonally opposite
wheel.
2. Remove any wheel trim. Insert
the tapered end of the lug nut
wrench behind wheel covers or
hubcaps and twist off.
3. Loosen each wheel metal lug nut
one-half turn counterclockwise but
do not remove them until the wheel
is raised off the ground.
2009 Grand Marquis (grn)
Owners Guide, 1st Printing
USA (fus)
Roadside Emergencies
193