Hummer 2010 H3 - Manual (Page 287)

Vehicle Care 10-21
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WARNING
Steam and scalding liquids from
a hot cooling system can blow
out and burn you badly. They
are under pressure, and if you
turn the surge tank pressure
cap — even a little — they can
come out at high speed. Never
turn the cap when the cooling
system, including the surge tank
pressure cap, is hot. Wait for the
cooling system and surge tank
pressure cap to cool if you ever
have to turn the pressure cap.
If coolant is needed, add the proper
mixture directly to the radiator, but
be sure the cooling system is cool
before this is done.
1. Remove the radiator pressure
cap when the cooling system,
including the upper radiator
hose, is no longer hot. Turn
the pressure cap slowly
counterclockwise about
one full turn.
If you hear a hiss, wait for that to
stop. A hiss means there is still
some pressure left.
2. Keep turning the cap to
remove it.
3. Fill the radiator with the proper
DEX‐COOL coolant mixture,
up to the base of the filler
neck. See Engine Coolant on
page 10‑19 for more information
about the proper coolant
mixture.
4. Fill the coolant recovery tank to
the FULL COLD mark.
5. Reinstall the cap on the coolant
recovery tank, but leave the
radiator pressure cap off.