2015 Cadillac ATS Owner Manual - Page 317

10-20 Vehicle Care 4. With the coolant surge tank pressure cap off and the surge tank service port cap open, start the engine and let it run until you can feel the upper radiator hose getting hot. Watch out for the engine cooling fan. By this time, the coolant level inside the coolant surge tank top chamber may be lower. If the level is lower, add more of the proper DEX-COOL coolant mixture to the surge tank top chamber until the level reaches the bottom of the fill neck. 5. Replace the surge tank pressure cap tightly and close the surge tank service port cap. Check the level in the surge tank top and bottom chambers when the cooling system has cooled down. If the coolant is not at the proper levels, repeat Steps 1-3 and reinstall the pressure cap and close the service port. If the coolant still is not at the proper levels when the system cools down again, see your dealer. 1. Remove the coolant surge tank pressure cap from the top chamber 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. If you hear a hiss, wait for that to stop. This will allow any pressure still left to be vented out the discharge hose. 2. Keep turning the pressure cap slowly and remove it. Open the surge tank service port cap to the lower chamber 3. Fill the surge tank top chamber with the proper DEX-COOL coolant mixture to the bottom of the fill neck. The top chamber needs to be completely full. Fill the surge tank bottom chamber through the service port to approximately half. Engine Overheating The vehicle has several indicators to warn of the engine overheating. There is an engine coolant temperature gauge and an engine coolant temperature warning light on the instrument cluster See Engine Coolant Temperature Gauge on page 5-13 and Engine Coolant Temperature Warning Light on page 5-22. The vehicle may also display a message on the Driver Information Center (DIC). See Engine Cooling System Messages on page 5-34. { Caution 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.