2007 Saturn Ion Owner's Manual - Page 304

By this time, the coolant level inside the coolant surge tank may be lower. If the level is lower, add more of the proper DEX-COOL® coolant mixture to the coolant surge tank until the level reaches the cold fill line. 5. Then replace the pressure cap. Be sure the pressure cap is hand-tight and fully seated. Check the level in the surge tank when the cooling system has cooled down. If the coolant is not at the proper level, repeat Steps 1 through 3 and reinstall the pressure cap. If the coolant is not at the proper level when the system cools down again, see your retailer. 3. Fill the coolant surge tank with the proper DEX-COOL® coolant mixture, to the cold fill line. 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. Watch out for the engine cooling fan. 304