Damage

Periodically inspect the tire treads and sidewalls for damage (such as bulges in the tread or sidewalls, cracks in the tread groove and separation in the tread or sidewall). If damage is observed or suspected have the tire inspected by a tire professional. Tires can be damaged during off-road use, so inspection after off-road use is also recommended.
WARNING: Age
Tires degrade over time depending on many factors such as
weather, storage conditions, and conditions of use (load, speed,
inflation pressure, etc.) the tires experience throughout their lives.
In general, tires should be replaced after six years regardless of tread wear. However, heat caused by hot climates or frequent high loading conditions can accelerate the aging process and may require tires to be replaced more frequently.
You should replace your spare tire when you replace the road tires or after six years due to aging even if it has not been used.
See also:
Interior
Depending on the second-row seating configuration, the Navigator carries
either seven or eight occupants and includes a standard, 60/40-split third-row
seat. Lincoln claims it is the only manufact ...
Resuming a set speed
Press and release RESUME. This will automatically return the vehicle to
the previously set speed. ...
Turning off speed control
To turn off the speed control, press OFF or turn off the ignition.
Note: When you turn off the speed control or the ignition, your speed
control set speed memory is erased. ...
