2010 Cadillac CTS Owner's Manual - Page 321

Vehicle Care 9-21 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 FROID/FULL COLD line on the side of the coolant surge tank. 5. Then replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated. 2. Then keep turning the pressure cap slowly and remove it. 3. Fill the coolant surge tank with the proper mixture, to slightly above the FROID/FULL COLD line on the side of the coolant surge tank. 4. With the coolant surge tank pressure cap off, start the engine and let it run until you can feel the upper radiator hose getting hot. The upper radiator hose is the top hose coming out of the radiator, on the passenger side of the vehicle. Watch out for the engine cooling fans. 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. Recheck the coolant level in the bottle next time you use your vehicle to insure the system is full when cold. See Engine Coolant on page 9‑18.