2012 Buick LaCrosse Owner's Manual - Page 266

8-10 Climate Controls Maintenance Air Intake Clear away any ice, snow, or leaves from the air intake at the base of the windshield that can block the flow of air into the vehicle. Passenger Compartment Air Filter The filter removes dust, pollen, and other airborne irritants from outside air that is pulled into the vehicle. The filter should be replaced as part of routine scheduled maintenance. See Maintenance Schedule on page 11‑3 for replacement intervals. For more information, see your dealer.