2012 Subaru Impreza Owner's Manual - Page 382

11-14 Maintenance and service 4. Open the air cleaner case and remove the air cleaner element. 5. Clean the inside of the air cleaner case and case cover with a damp cloth and install a new air cleaner element. Spark plugs & Recommended spark plugs For the recommended spark plugs, refer to "Electrical system" F12-3. 6. If the air cleaner case has been removed, insert the three projections on the air cleaner case into the slits on the air cleaner case cover. 7. Install in the reverse order of removal. It may be difficult to replace the spark plugs. It is recommended that you have the spark plugs replaced by your SUBARU dealer. The spark plugs should be replaced according to the maintenance schedule in the "Warranty and Maintenance Booklet". CAUTION . When disconnecting the spark plug cables, always grasp the spark plug cap, not the cables. . Make sure the cables are replaced in the correct order.