Chevrolet 2008 Optra Owner's Manual page 219

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 6-4 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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