2003 Buick Regal Owner's Manual - Page 226

To check or replace the engine air cleaner/filter, do the following: 1. Loosen the screw and clamp on the air duct. 2. Lift up on the two clips located on the top of the filter assembly. Refer to the Maintenance Schedule to determine when to replace the air filter. See Part A: Scheduled Maintenance Services on page 6-4. Operating the engine with the air cleanedfilter off can cause you or others to be burned. The air cleaner not only cleans the air, stops it flame if the engine backfires. If isn't there it and the engine backfires, you could be burned. Don't drive with it off, and be careful working off. on the engine with the air cleaner/filter 3. Then disconnect the duct and reposition it while removing the side cover. 4. Pull out the filter. 5. Replace the filter if needed. 6. Be sure to reinstall the filter and install the cover tightly when you are finished. 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 cleanedfilterin place when you're driving. 5-2 1