1998 GMC Sonoma Owner's Manual - Page 227

How to Add Coolant to the Coolant Recovery Tank Heater and radiatorhoses, and other engine parts, can be very hot. Don't touch them. If you do, you can be burned. Don't run the engine if there is a leak. If you run the engine, it could all coolant. That could lose cause an engine fire, and could be burned. you Get any leak fixed before drive the vehicle. you I f you haven't found a problem yet? but the coolant level isn't at the ADD mark, add a 50/50 mixture of c.lo.cr,z ~ ~ ~ u(preferably distilled)and DEX-COOL' engine rer coolant at the coolant recovery tank. (See "Engine Coolant" in the Index for more information.) A CL'UTION: - NOTICE: Engine damage from running your engine without coolant isn't coveredby your warranty. ~ ~~ ~~ ~ If there seems to be no leak, start the engine again. See if the engine cooling fan speed increases when idle speed is doubled by pushing the accelerator pedal down. If it doesn't, your vehicle needs service. Turn off the engine. Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid like alcohol, can boil before the proper coolant mixturewill. Your vehicle's coolant warning systemis set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot but wouldn't you get the overheat warning.Your engine could catch fire andyou or others couldbe burned. Use a 50/50 mixture of clean water and DEX-COOL@coolant. 5-15