Pontiac Montana SV6 2007 Owner's Manual page 439

CAUTION:
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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 radiator pressure cap — even
a little — they can come out at high
speed. Never turn the cap when the
cooling system, including the radiator
pressure cap, is hot. Wait for the cooling
system and radiator pressure cap to cool
if you ever have to turn the pressure cap.
How to Add Coolant to the Radiator
Notice: Your engine has a specific radiator fill
procedure. Failure to follow this procedure
could cause your engine to overheat and be
severely damaged.
Turn the pressure cap slowly counterclockwise.
If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left, close
the cap and wait for the system to cool down.
1. You can remove the
radiator pressure
cap when the
cooling system,
including the radiator
pressure cap and
upper radiator hose,
is no longer hot.
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