Chevrolet 2007 Optra Owner's Manual page 265

To inspect or replace the filter, do the following:
1. Remove the four screws that hold the cover on.
2. Lift off the cover.
3. Inspect or replace the engine air cleaner/filter.
4. Put the cover back on tightly and tighten
the screws.
See Part A: Scheduled Maintenance Services on
page 358 for replacement intervals.
CAUTION:
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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 flames 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.
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