2005 Buick LaCrosse Owner's Manual - Page 298

What to Use Use a mixture of one-half clean, drinkable water and one-half DEX-COOL® engine coolant which will not damage aluminum parts. If this coolant mixture is used, nothing else needs to be added. If coolant needs to be added more than four times a year, have your dealer check the cooling system. Notice: If you use the proper coolant, you do not have to add extra inhibitors or additives which claim to improve the system. These can be harmful. Checking Coolant {CAUTION: Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid such as alcohol, can boil before the proper coolant mixture will. Your vehicle's coolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot but you would not get the overheat warning. Your engine could catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and DEX-COOL® coolant. Notice: If you use an improper coolant mixture, your engine could overheat and be badly damaged. The repair cost would not be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts. 5-22 The coolant recovery tank is located in the engine compartment toward the rear of the engine on the passenger's side of the vehicle. See Engine Compartment Overview on page 5-12 for more information on location. 3.8L V6 engine shown, 3.6L V6 engine similar The vehicle must be on a level surface when checking the coolant level. When the engine is cold, the coolant level should be at the cold fill line or a little higher. The cold fill line is near the bottom of the surge tank and has an arrow pointing down at it.