2011 Chevrolet Volt Owner's Manual - Page 389

Vehicle Care If coolant is needed, add the proper DEX-COOL coolant mixture at the coolant surge tank. 10-23 Engine Overheating The vehicle has an indicator to warn of engine overheating. If the decision is made not to lift the hood when this warning appears, get service help right away. See Roadside Assistance Program on page 13‑6. The coolant surge tank pressure cap can be removed when the cooling system, including the surge tank pressure cap and upper radiator hose, is no longer hot. 1. Turn the pressure cap slowly counterclockwise. If a hiss is heard, wait for that to stop. A hiss means there is still some pressure left. 2. Keep turning the cap and remove it. If the decision is made to lift the hood, make sure the vehicle is parked on a level surface. 3. Fill the coolant surge tank with the proper mixture to the cold fill line. 4. Replace the pressure cap. Be sure the pressure cap is hand‐tight and fully seated. 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. Then check to see if the engine cooling fans are running. If the engine is overheating, the fans should be running. If they are not, do not continue to run the vehicle and have the vehicle serviced. Notice: Engine damage from running the engine without coolant is not covered by the warranty.