2003 Cadillac DeVille Owner's Manual - Page 300

If No Steam Is Corning From Your Engine An overheat warning, along with a low coolant message, can indicate a serious problem. See DlC Warnings and Messages on page 3-60. If you get an engine overheat warning with no low coolant message, 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 hill on a hot day. Stop after high-speed driving. Idle for long periods in traffic. Tow a trailer. If you get the overheat warning with no sign of steam, try this for a minute orso: 1. In heavy traffic, let the engine idle in NEUTRAL (N) while stopped. If it safe to do so, pull of the road, shift ;to PARK (P) or NEUTRAL (N) and let the engine idle. 2. Set the temperature control to the highest heat setting and open the windows, as necessary. 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 your vehicle right away. If there's still no sign of steam, idle the engine for three minutes while you're parked. If you still have the warning, turn off the engine and get everyone out of the vehicle until it cools down. Also, see "Overheated Engine Protection Operating Mode" listed previously in this section. You may decide not to lift the hood but to get service help right away. 5-29