2009 Cadillac Escalade Owner's Manual - Page 463

If no coolant is visible in the surge tank, add coolant as follows: 1. You can remove the coolant surge tank pressure cap when the cooling system, including the coolant surge tank pressure cap and 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. 2. Keep turning the pressure cap slowly and remove it. 3. Fill the coolant surge tank with the proper mixture to the FULL COLD mark. 6-29