2009 Chevrolet Silverado 2500 HD Extended Cab Owner's Manual - Page 446

If No Steam Is Coming From The Engine Compartment The ENGINE OVERHEATED STOP ENGINE or the ENGINE OVERHEATED IDLE ENGINE message, along with a low coolant condition, can indicate a serious problem. If you get an engine overheat warning, but see or hear no steam, the problem may not be too serious. Sometimes the engine can get a little too hot when you: If you get the ENGINE OVERHEATED STOP ENGINE or the ENGINE OVERHEATED IDLE ENGINE message with no sign of steam, try this for a minute or so: 1. Turn the air conditioning off. 2. Turn the heater on to the highest temperature and to the highest fan speed. Open the windows as necessary. 3. If you are stopped in a traffic jam, apply the brake, shift to N (Neutral); otherwise, shift to the highest gear while driving - D (Drive) or 3 (Third). 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 five minutes while parked. If the warning is still displayed, turn off the engine until it cools down. Also, see "Overheated Engine Protection Operating Mode" later in this section. Climb a long hill on a hot day. Stop after high-speed driving. Idle for long periods in traffic. Tow a trailer. See Towing a Trailer on page 4-50. 5-36