2007 Chevrolet Cobalt Owner's Manual - Page 300

Checking Intercooler System Coolant (2.0L L4 Supercharged Engine Only) {CAUTION: 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. 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 284 for more information on location. 300