Chevrolet 2011 HHR Owner's Manual page 316

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 surge tank
pressure cap even a little
out at high speed. Never turn the cap when the
cooling system, including the surge tank pressure
cap, is hot. Wait for the cooling system and surge
tank pressure cap to cool if you ever have to turn
the pressure cap.
6-28
they can come
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 coolant recovery tank, add
coolant at the pressure cap as follows:
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 to be
vented.
2. Then keep turning the pressure cap and remove it.
3. Add the proper DEX-COOL coolant mixture to the
coolant fill port, up to the base of the port. See
Engine Coolant on page 6 25 Engine Coolant for
more information about the proper coolant mixture.
4. Rinse or wipe any spilled coolant from the engine
and the compartment.
1. Remove the pressure
cap when the cooling
system, including the
pressure cap and
upper radiator hose,
is no longer hot.