1998 Chevrolet Astro Owner's Manual - Page 236

If No Steam Is ComingFrom Your Engine If you get the overheat warning but see or hear no steam, the problem may not betoo 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. 0 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, push the accelerator until the engine speed is about twice as as normal fast idle speed. Bring the engine speed back to normal idle speed after twoor three minutes. Now see if the warning stops. But then, if you still have the warning,turn ofs the engine nncl 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. Tow a trailer. See "Driving on Grades" in the Index. If you get the overheat warning with no sign of steam, try this for a minute or so: I. Turn off your air conditioner. 2. Turn on your heater to full hot at the highest fan speed and open the windowas necessary. 3. If you're in a traffic jam, shift to NEUTRAL (N); otherwise, shift to the highest gear while driving -- DRIVE (D). 5-14