2005 GMC Envoy Owner's Manual - Page 352

When to Inspect the Engine Air Cleaner/Filter Inspect the air cleaner/filter at the Maintenance II intervals and replace at the first oil change after each 50,000 mile (83 000 km) interval. See Scheduled Maintenance on page 6-4 for more information. If you are driving in dusty/dirty conditions, inspect the filter at each engine oil change. 3. Inspect or replace the engine air cleaner/filter. 4. Reinstall the cover and tighten the screws. {CAUTION: Operating the engine with the air cleaner/filter off can cause you or others to be burned. The air cleaner not only cleans the air; it helps to stop flame if the engine backfires. If it is not there and the engine backfires, you could be burned. Do not drive with it off, and be careful working on the engine with the air cleaner/filter off. 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 cleaner/filter in place when you are driving. How to Inspect the Engine Air Cleaner/Filter To inspect the air cleaner/filter remove the filter from the vehicle and lightly shake the filter to release loose dust and dirt. If the filter remains caked with dirt, a new filter is required. To inspect or replace the engine air cleaner/filter, do the following: 1. Remove the screws on the engine air cleaner/filter and lift off the cover. 2. Remove the air cleaner/filter from the housing. Care should be taken to dislodge as little dirt as possible. 5-20