1997 Pontiac Bonneville Owner's Manual - Page 230

If No Steam Is Coming From Your Engine If you get the overheat warning but seeor hear no steam, theproblem may not be too serious. Sometimes the engine can geta little too hot when you: Climb a long hill on a hot day. Stop after high-speed driving. Idle for long periods in traffic. Tow a trailer. If you no longer have the overheat warning, can you drive. Just to be safe, drive slower for about 10 minutes. If the warning doesn'tcome back on, you can drive normally. If the warning continues, pull over, stop, andpark your vehicle right away. If there's still no sign of steam, you can idle theengine for two or three minutes while you're parked, to see if the warning stops. Butthen, if you still have the warning, turn off the engine and get everyone out of the vehicle until it cools down. You may decide not to lift the hood but to get service help right away. If you get the overheat warning with sign of steam, no try this for a minute or so: 1. Turn off your air conditioner. 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 (@) or DRIVE (D). 5-17