2006 Cadillac STS-V Owner's Manual - Page 349

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 largest of the hoses which comes out of the radiator, on the passenger's side of the vehicle. 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/FROID 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. 3. Fill the coolant surge tank with the proper DEX-COOL® coolant mixture, to slightly above the FULL COLD/FROID line on the side of the coolant surge tank. Start the engine and allow it to warm up. If the CHECK COOLANT LEVEL message does not appear on the Driver Information Center (DIC), the coolant is at the proper fill level. If the CHECK COOLANT LEVEL message does appear, repeat Steps 1 to 3 then reinstall the pressure cap, or see your GM dealer. 5-37