Cadillac 2004 CTS - Manual (Page 309)

When to Inspect the Engine
Air Cleaner/Filter
Inspect the air cleaner/filter at every oil change and
replace it at the first oil change after 25,000 miles
(40 000 km)
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 caked with dirt,
a new filter is required.
To inspect or replace the filter, do the following:
1. Remove the two screws located on the sides of
the cover.
2. Lift the cover off.
3. Pull out the old engine air cleaner/filter.
4. Install a new engine air cleaner/filter, if needed.
See Normal Maintenance Replacement Parts on
page 6-15 for the correct part number for the filter.
5. Reinstall the cover by reversing Steps 1 and 2.
{ CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned.
The air cleaner not only cleans the air, it helps
to stop flame if the engine backfires. If it is
not there and the engine backfires, you could
be burned. Do not drive with it off, and be
careful working on the engine with the air
cleaner/filter off.
Notice: If the air cleaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can easily get
into your engine, which will damage it. Always have
the air cleaner/filter in place when you are driving.
5-23