2009 Hummer H3T Owner's Manual - Page 215

Driving Your Vehicle Run the engine for short periods only as needed to keep warm, but be careful. To save fuel, run the engine for only short periods as needed to warm the vehicle and then shut the engine off and close the window most of the way to save heat. Repeat this until help arrives but only when you feel really uncomfortable from the cold. Moving about to keep warm also helps. If it takes some time for help to arrive, now and then when you run the engine, push the accelerator pedal slightly so the engine runs faster than the idle speed. This keeps the battery charged to restart the vehicle and to signal for help with the headlamps. Do this as little as possible to save fuel. 4-33 If Your Vehicle is Stuck in Sand, Mud, Ice, or Snow Slowly and cautiously spin the wheels to free the vehicle when stuck in sand, mud, ice, or snow. See Rocking Your Vehicle to Get It Out on page 4-34. If the vehicle has a traction system, it can often help to free a stuck vehicle. Refer to the vehicle's traction system in the Index. If stuck too severely for the traction system to free the vehicle, turn the traction system off and use the rocking method. { CAUTION If you let your vehicle's tires spin at high speed, they can explode, and you or others could be injured. The vehicle can overheat, causing an engine compartment fire or other damage. Spin the wheels as little as possible and avoid going above 35 mph (55 km/h) as shown on the speedometer. For information about using tire chains on the vehicle, see Tire Chains on page 5-65.