2009 Chevrolet Cobalt Owner's Manual - Page 291

If No Steam Is Coming From The Engine Compartment If an engine overheat warning is displayed but no steam can be seen or heard, the problem may not be too serious. Sometimes the engine can get a little too hot when the vehicle: If the temperature overheat gage is no longer in the overheat zone or an overheat warning no longer displays, the vehicle can be driven. Continue to drive the vehicle slow for about 10 minutes. Keep a safe vehicle distance from the car in front of you. If the warning does not come back on, continue to drive normally. If the warning continues, pull over, stop, and park the vehicle right away. If there is no sign of steam, idle the engine for three minutes while parked. If the warning is still displayed, turn off the engine until it cools down. Climbs a long hill on a hot day. Stops after high-speed driving. Idles for long periods in traffic. Tows a trailer. If the overheat warning is displayed with no sign of steam: 1. Turn the air off. 2. Turn the heater on to the highest temperature and to the highest fan speed. Open the windows as necessary. 3. In heavy traffic, let the engine idle in N (Neutral) for automatic transmission or NEUTRAL for manual transmission, while stopped. If it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and let the engine idle. 5-33