Chevrolet 2005 Cobalt Owner's Manual page 244

Checking Intercooler System Coolant
(2.0L L4 Supercharged Engine Only)
The intercooler system fill neck is located in the front of
the engine compartment, near the center of the
vehicle. See Engine Compartment Overview on
page 5-12 for more information on location.
5-26
CAUTION:
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Turning the fill neck pressure cap when the
engine and intercooler are hot can allow
steam and scalding liquids to blow out and
burn you badly. Never turn the fill neck
pressure cap — even a little — when the
engine and intercooler are hot.
Park your vehicle on a level surface and turn off the
engine. When the engine is cold, the coolant level
should be visible within the horizontal tube section of
the fill neck. When the engine is warm, the coolant level
could be as high as the FULL HOT line on the fill
neck, or a little higher.