2011 Chevrolet Express 1500 Cargo Owner's Manual - Page 294

10-24 Vehicle Care 8. Replace the pressure cap. At any time during this procedure if coolant begins to flow out of the filler neck, reinstall the pressure cap. 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. See Roadside Assistance Program (U.S. and Canada) on page 13‑8 or Roadside Assistance Program (Mexico) on page 13‑10. If the decision is made to lift the hood, make sure the vehicle is parked on a level surface. Then check to see if the engine cooling fans are running. If the engine is overheating, both fans should be running. If they are not, do not continue to run the engine and have the vehicle serviced. See if the engine cooling fan speed increases when idle speed is doubled by pushing the accelerator pedal down. If it does not, the vehicle needs service. Turn off the engine. Notice: Engine damage from running the engine without coolant is not covered by the warranty. Notice: If the engine catches fire because of being driven with no coolant, the vehicle can be badly Engine Overheating 6. Start the engine and let it run until the upper radiator hose can be felt getting hot. Watch out for the engine cooling fan. 7. By this time, the coolant level inside the radiator filler neck may be lower. If the level is lower, add more of the proper DEX-COOL coolant mixture through the filler neck until the level reaches the base of the filler neck. If the vehicle has a diesel engine, see the Duramax diesel supplement for more information. The vehicle has an indicator to warn of engine overheating. There is an engine coolant temperature gauge on the vehicle's instrument panel. See Engine Coolant Temperature Gauge on page 5‑15 for more information. If the decision is made not to lift the hood when this warning appears, but instead get service help right away.