2008 Buick Enclave Owner's Manual - Page 332

3. Keep turning the pressure cap slowly, and remove it. 1. To remove the panel that covers the radiator cap, detach fasteners and lift off panel. 2. Remove the radiator pressure cap when the cooling system, including the upper radiator hose, is no longer hot. Turn the pressure cap slowly counterclockwise about one full turn. If you hear a hiss, wait for that to stop. A hiss means there is still some pressure left. 4. Fill the radiator with the proper DEX-COOL® coolant mixture, up to the base of the filler neck. See Engine Coolant on page 5-22 for more information about the proper coolant mixture. 5-32