Buick 2011 Lucerne Owner's Manual page 181

3. To remove the air filter, insert a tool between the
air filter and the compartment wall on the outboard
side of the vehicle. Then, push in to flatten the pin
holding the air filter in place. Gently remove the air
filter and any loose debris that may be inside the
air filter compartment.
4. Insert the new air filter by pushing until you hear a
click. Reinstall the push pin and snap the cover
into place.
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