Chevrolet 2010 HHR Owner's Manual page 336

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 fill port, up to the base of the port. See
Engine Coolant on page 6 29 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.
®
coolant mixture to the
5. Then fill the coolant recovery tank to the COLD
FILL (A) line.
6. Put the cap back on the coolant recovery tank, but
leave the pressure cap off.
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