2009 Buick Lucerne Owner's Manual - Page 315

4. With the coolant surge tank cap off, start the engine and let it run until you can feel the upper radiator hose getting hot. Watch out for the engine cooling fans. By this time, the coolant level inside the coolant surge tank may be lower. If the level is lower, add more of the proper mixture to the coolant surge tank until the level reaches the FULL COLD mark on the side of the coolant surge tank. 5. Then replace the cap. Be sure the cap is hand-tight and fully seated. If coolant is needed, add the proper DEX-COOL® coolant mixture at the coolant recovery tank. Notice: If the pressure cap is not tightly installed, coolant loss and possible engine damage may occur. Be sure the cap is properly and tightly secured. Engine Coolant (3.9L Engine) The cooling system in the vehicle is filled with DEX-COOL® engine coolant. This coolant is designed to remain in the vehicle for five years or 150,000 miles (240 000 km), whichever occurs first. The following explains the cooling system and how to check and add coolant when it is low. If there is a problem with engine overheating, see Engine Overheating on page 5-36. 5-31