1998 GMC Sonoma Owner's Manual - Page 224

Engine Overheating You will find a coolant temperature gage on your vehicle's instrument panel. See "Gages" in the Index. If Steam Is Coming From Your Engine ' Steam from an overheated engine can burn you badly, even if you just open the hood. Stay away from the engine you see or hear steam coming if from it. Just turn it and get everyone away off from thevehicle until itcools down. Wait until there is no sign steam or coolant before of you open thehood. If you keep drivingwhen your engine is overheated, the liquids in it can catch fire. or You others could be badly burned. Stop your engine if it overheats, and get outthe vehicle until the of engine is cool. I NOTICE: If your engine catches fire because keep you vehicle can be driving with no coolant, your badly damaged. Thecostly repairs would not be covered by your warranty. I