Cadillac 2007 CTS Owner's Manual page 367

CAUTION:
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Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can
boil before the proper coolant mixture will.
Your vehicle's coolant warning system is
set for the proper coolant mixture. With
plain water or the wrong mixture, your
engine could get too hot but you would
not get the overheat warning. Your engine
could catch fire and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
Notice: In cold weather, water can freeze and
crack the engine, radiator, heater core and
other parts. Use the recommended coolant and
the proper coolant mixture.
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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.
If no coolant is visible in the surge tank, add
coolant as follows:
1. You can remove the coolant surge tank
®
coolant.
CAUTION:
pressure cap when the cooling system,
including the coolant surge tank pressure cap
and upper radiator hose, is no longer hot.
Turn the pressure cap slowly counterclockwise
about one-quarter turn and then stop.
If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left.
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