1998 GMC Suburban Owner's Manual - Page 264

If No Steam Is Coming From Your Engine I f you get the 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: Climb a long h i l l on a hot day. Stop after high-speed driving. Idle for long periods in traffic. Tow a trailer. See "Driving on Grades" i n the Index. If you no longer have the overheat warning, you can drive. Just to be safe, drive slower for about 10 minutes. If the warning doesn't come back on, you can drive normally. If the warning continues, pull over, stop, and park p u r vehicle right away. If there's still no sign of steam, push the accelerator until the engine speed is about twice as fast as normal idle speed. Bring the engine speed back to normal idle speed after two or three minutes. Now see if the warning stops. But then, if you still have the warning, t ~ t m tlze off engine u17d get everyone out o the vehicle until it f cools down. You may decide not to lift the hood but to get service help right away. If you get the overheat warning with no sign of steam, try this for a minute or so: I . If you have an air conditioner, turn it off. 2. Turn on your heater to full hot at the highest fan speed and open the window as necessary. 3. If you're in a traffic jam, shift to NEUTRAL (N); otherwise, shift to the highest gear while driving -- AUTOMATIC OVERDRIVE (@). 5-14