Chevrolet TrailBlazer 2007 Owner's Manual page 419

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.
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 the coolant in the coolant recovery tank is
at the FULL COLD mark, start your vehicle.
If the overheat warning continues, there is one
more thing you can try. You can add the proper
coolant mixture directly to the radiator, but be sure
the cooling system is cool before you do it.
CAUTION:
{
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.
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