2010 Cadillac CTS Owner's Manual - Page 319

Vehicle Care What to Use 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: . 9-19 Checking Coolant The vehicle must be on a level surface when checking the coolant level. The engine coolant reservoir is located in the engine compartment on the driver side of the vehicle. See Engine Compartment Overview on page 9‑6. Check to see if coolant is visible in the surge tank. If the coolant inside the surge 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 surge tank, but be sure the cooling system is cool before this is done. See Engine Coolant on page 9‑18 for more information. { WARNING 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 −37°C (−34°F), outside temperature. Gives boiling protection up to 129°C (265°F), engine temperature. Protects against rust and corrosion. 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.