GMC 1999 Sierra 1500 Pickup Owner's Manual page 310

Service & Appearance Care
I
IC\
Operating the engine with the air cleaner off can cause you or others
to be burned. The air cleaner not only cleans the air,
it
stops flame
if the engine backfires. If it isn't there, and the engine backfires, you
could be burned. Don't drive with it off, and be careful working on
the engine with the air cleaner off.
If the air cleaner is off, a backfire can cause a damaging engine fire. And,
dirt can easily get into your engine, which will dan le it. Alway!
3
tl
air cleaner in place when you're driving.
To
remove the air cleaner filter on a gas engine, turn the wing nuts
counterclockwise. Remove the cover and change the filter.
fi 3 1 Fnning
6.5L
Engine
K2151
On a 6.2L diesel engine there are two wing nuts. On a 6.5L diesel engine,
unhook the clips.
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