2004 Cadillac DeVille Owner's Manual - Page 311

If No Steam Is Coming From Your Engine An overheat warning, along with a low coolant message, can indicate a serious problem. See DIC Warnings and Messages on page 3-62. 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: If you get the overheat warning with no sign of steam, try this for a minute or so: 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 does not come back on, you can drive normally. If the warning continues, pull over, stop, and park your vehicle right away. If there is still no sign of steam, idle the engine for three minutes while you are 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. Climb a long hill on a hot day. Stop after high-speed driving. Idle for long periods in traffic. Tow a trailer. 5-31