Cadillac CTS Owner's Manual page 336

10-16 Vehicle Care
When to Inspect the Engine
Air Cleaner/Filter
Inspect the air cleaner/filter at the
scheduled maintenance intervals
and replace it at the first oil change
after each 80 000 km (50,000 mile)
interval. See Maintenance Schedule
on page 11 4, for more information.
If you are driving in dusty/dirty
conditions, inspect the filter at each
engine oil change.
How to Inspect the Engine
Air Cleaner/Filter
To inspect the air cleaner/filter,
remove the filter from the vehicle
and lightly shake the filter to release
loose dust and dirt. If the filter
remains covered with dirt, a new
filter is required.
To inspect or replace the engine air
cleaner/filter:
1. Turn the ignition off.
2. Remove the side cover by
pulling up on the front of the
cover.
3. Disconnect the electrical
connector from the air box.
4. Loosen the screw on the clamp
holding the air outlet duct in
place. Do not remove the clamp.
Move the duct aside.
5. Remove the hose from the air
cleaner housing mounting arm.
Move the hose aside.