Hummer 2004 H2 - Manual (Page 341)

Adding Coolant
If you need more coolant, add the proper DEX-COOL ®
coolant mixture at the surge tank, but only when the
engine is cool.
{ CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight.
Coolant Surge Tank Pressure Cap
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. See Engine
Compartment Overview on page 5-12 for more
information on location.
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.
Engine Overheating
You will find a coolant temperature gage on your
vehicle’s instrument panel. See Engine Coolant
Temperature Gage on page 3-35. In addition, you will
find an ENGINE COOLANT HOT, ENGINE
OVERHEATED and a REDUCED ENGINE POWER
message in the DIC on the instrument panel. See DIC
Warnings and Messages on page 3-56.
5-27