Hummer 2006 H3 - Manual (Page 299)

Radiator Pressure Cap
Notice: If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
See Engine Compartment Overview on page 5-12 for
more information on location.
Engine Overheating
You will find a coolant temperature gage on your
vehicle’s instrument panel. See Engine Coolant
Temperature Gage on page 3-34.
Your air conditioning may stop working if your engine
is too hot. This is normal and helps cool the engine.
If Steam Is Coming From Your Engine
{ CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood.
Stay away from the engine if you see or hear
steam coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch fire.
You or others could be badly burned. Stop
your engine if it overheats, and get out of
the vehicle until the engine is cool.
Notice: If your engine catches fire because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not
be covered by your warranty.
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