2009 Buick LaCrosse Owner's Manual - Page 300

How to Add Coolant to the Cooling System (5.3L V8 Engine) 1. You can remove the pressure cap when the cooling system, including the pressure cap and upper radiator hose is no longer hot. Turn the pressure cap slowly counterclockwise. If you hear a hiss, wait for that to stop. A hiss means that there is still some pressure left. 2. Then keep turning the pressure cap and remove it. 3. Fill the cooling system with the proper DEX-COOL® coolant mixture, up to the base of the filler neck. See Engine Coolant on page 5-25 Engine Coolant Engine Coolant for more information about the proper coolant mixture. 4. Rinse or wipe any spilled coolant from the engine and the compartment. 5. Then fill the coolant recovery tank to the COLD FILL line. 6. Install the coolant recovery tank cap and the pressure cap. After a day or two of driving, when the engine is cold, check the coolant level in the recovery tank. If it is low, refill it to the COLD FILL line. If the coolant in the recovery tank is constantly low, you should have a dealer/retailer service department inspect the vehicle for leaks. 5-30