Cadillac STS 2011 Owner's Manual page 485

Once Every Two Years
Vehicles using DOT 4 brake fluid only: Brake fluid
replacement.
First Engine Oil Change After Every
40 000 km/25,000 Miles
Passenger compartment air filter replacement
(or every 24 months, whichever occurs first).
More frequent replacement may be needed if
you drive in areas with heavy traffic, areas with
poor air quality, or areas with high dust levels.
Replacement may also be needed if you notice
reduced air flow, windows fogging up, or odors.
Your dealer can help you determine when it is the
right time to replace the filter.
First Engine Oil Change After Every
80 000 km/50,000 Miles
Engine air cleaner filter replacement. See Engine
Air Cleaner/Filter on page 6 21.
Automatic transmission fluid and filter change
(severe service) for vehicles mainly driven in heavy
city traffic in hot weather, in hilly or mountainous
terrain, when frequently towing a trailer, or used for
taxi, police, or delivery service. See Automatic
Transmission Fluid on page 6 23.
7-6
All wheel drive only: Transfer case fluid change
(severe service) for vehicles mainly driven when
frequently towing a trailer, or used for taxi, police,
or delivery service. Check vent hose at transfer
case for kinks and proper installation. Check to be
sure vent hose is unobstructed, clear, and free of
debris.
Evaporative control system inspection. Check all
fuel and vapor lines and hoses for proper hook up,
routing, and condition. Check that the purge valve,
if the vehicle has one, works properly. Replace as
needed. An Emission Control Service. The U.S.
Environmental Protection Agency or the California
Air Resources Board has determined that the
failure to perform this maintenance item will not
nullify the emission warranty or limit recall liability
prior to the completion of the vehicle's useful life.
We, however, urge that all recommended
maintenance services be performed at the
indicated intervals and the maintenance be
recorded.