GMC 2012 Sierra Series Owner's Manual page 422

10-22 Vehicle Care
How to Add Coolant to the
Coolant Surge Tank for
Gasoline Engines
If the vehicle has a diesel engine,
see Cooling System in the
Duramax Diesel Supplement for the
proper coolant fill procedure.
WARNING
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.
Notice: This vehicle has a
specific coolant fill procedure.
Failure to follow this procedure
could cause the engine to
overheat and be severely
damaged.
WARNING
An electric engine cooling fan
under the hood can start up even
when the engine is not running
and can cause injury. Keep
hands, clothing, and tools away
from any underhood electric fan.
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 coolant surge tank pressure
cap even a little they can
come out at high speed. Never
turn the cap when the cooling
system, including the coolant
surge tank pressure cap, is hot.
Wait for the cooling system and
coolant surge tank pressure cap
to cool if you ever have to turn
the pressure cap.
I n f o r ma t i o n P r o v i d e d b y :
If no coolant is visible in the surge
tank, add coolant as follows:
1. Remove the coolant surge tank
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 full
turn. If a hiss is heard, wait for
that to stop. A hiss means there
is still some pressure left.
2. Keep turning the pressure cap
slowly, and remove it.