FORD 2003 F-150 v.1 - Manual (Page 250)

AIR FILTER MAINTENANCE
Refer to the scheduled maintenance guide for the appropriate intervals
for changing the air filter element.
When changing the air filter element, use only the Motorcraft air filter
element listed. Refer to Motorcraft Part Numbers.
Note: Do not start your engine with the air cleaner removed and do not
remove it while the engine is running.
Changing the air filter element
1. Loosen the clamp that secures
the air filter element in place.
2. Carefully separate the two halves
of the air filter housing.
3. Remove the air filter element
from the open end of the air filter
housing.
4. Install a new air filter element, ensuring the notch on the top half of
the air filter housing lines up with the notch on the bottom half of air
filter housing. Be careful not to crimp the filter element edges between
the air filter housing. This could cause filter damage and allow
unmetered air to enter the engine if not properly seated.
5. Replace the two halves of the air filter housing and secure the clamp.
Maintenance and Specifications
250