2009 Pontiac G3 Owner's Manual - Page 229

{ CAUTION: Turning the surge tank pressure cap when the engine and radiator are hot can allow steam and scalding liquids to blow out and burn you badly. Never turn the surge tank pressure cap - even a little - when the engine and radiator are hot. When the engine is cold, the coolant level should be between the Maximum (A) and Minimum (B) marks on the coolant surge tank. The level rises at engine operation temperature and drops again when the engine cools down. The coolant should be between the Maximum (A) and Minimum (B) marks, when the engine is cold. If it is not, there could be a leak in the cooling system. The engine coolant surge tank is located in the rear of the engine compartment on the driver side of the vehicle. See Engine Compartment Overview on page 5-12 for more information on location. 5-25