Chevrolet 2009 Kodiak Owner's Manual page 248

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.
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. Then keep turning the pressure cap slowly, and
remove it.
5-46
1. You can 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.
3. Fill the coolant surge tank with the proper mixture,
to the FULL COLD mark.