2009 GMC Acadia Owner's Manual - Page 306

5-20 Service and Appearance Care Use a 50/50 mixture of clean, drinkable water and DEX-COOL coolant. If using this mixture, nothing else needs to be added. This mixture: Notice: If extra inhibitors and/or additives are used in the vehicle's cooling system, the vehicle could be damaged. Use only the proper mixture of the engine coolant listed in this manual for the cooling system. See Recommended Fluids and Lubricants on page 6-12 for more information. What to Use { CAUTION Adding only plain water to the cooling system can be dangerous. Plain water, or some other liquid such as alcohol, can boil before the proper coolant mixture will. The vehicle's coolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, the engine could get too hot but you would not get the overheat warning. The engine could catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant. • Gives freezing protection down to −34°F (−37°C), outside temperature. 265°F (129°C), engine temperature. • Gives boiling protection up to • Protects against rust and corrosion. Checking Coolant The vehicle must be on a level surface when checking the coolant level. Check to see if coolant is visible in the coolant recovery tank. If the coolant inside the coolant recovery tank is boiling, do not do anything else until it cools down. If coolant is visible but the coolant level is not at or above the FULL COLD mark, add a 50/50 mixture of clean, drinkable water and DEX-COOL coolant at the coolant recovery tank, but be sure the cooling system is cool before this is done. See Engine Coolant on page 5-19 for more information. • Will not damage aluminum parts. • Helps keep the proper engine temperature. Notice: If an improper coolant mixture is used, the engine could overheat and be badly damaged. The repair cost would not be covered by the vehicle warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core, and other parts.