Hummer 2007 H2 Owner's Manual page 417

Checking Coolant
CAUTION:
{
Turning the surge tank pressure cap when
the engine and radiator are hot can allow
steam and scalding liquids to blow out
and burn you badly. Never turn the surge
tank pressure cap — even a little — when
the engine and radiator are hot.
The coolant surge tank
is located in the engine
compartment on the
passenger's side of the
vehicle. See Engine
Compartment Overview
on page 402 for more
information on location.
The vehicle must be on a level surface. When
your engine is cold, the coolant level should be at
the FULL COLD mark.
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 and fully seated.
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