2010 GMC Savana 2500 Cargo Owner's Manual - Page 296

If No Steam Is Coming From The Engine Compartment If an engine overheat warning is displayed but no steam can be seen or heard, the problem may not be too serious. Sometimes the engine can get a little too hot when the vehicle: vehicle distance from the car in front of you. If the warning does not come back on, continue to drive normally. If the warning continues, pull over, stop, and park the vehicle right away. If there is still no sign of steam, push down the accelerator until the engine speed is about twice as fast as normal idle speed for at least three minutes while you are parked. If you still have the warning, turn off the engine until it cools down. You may decide not to lift the hood but to get service help right away. Climbs a long hill on a hot day. Stops after high-speed driving. Idles for long periods in traffic. Tows a trailer. See "Driving on Grades" under Towing a Trailer on page 5-26. If the overheat warning is displayed with no sign of steam: 1. Turn the air off. 2. Turn the heater on to the highest temperature and to the highest fan speed. Open the windows as necessary. 3. In heavy traffic, let the engine idle in N (Neutral) while stopped. If it is safe to do so, pull off the road, shift to P (Park) or N (Neutral) and let the engine idle. If the temperature overheat gage is no longer in the overheat zone or an overheat warning no longer displays, the vehicle can be driven. Continue to drive the vehicle slow for about 10 minutes. Keep a safe 6-34 Engine Fan Noise Your vehicle has a clutched engine cooling fan. When the clutch is engaged, the fan spins faster to provide more air to cool the engine. In most everyday driving conditions, the fan is spinning slower and the clutch is not fully engaged. This improves fuel economy and reduces fan noise. Under heavy vehicle loading, trailer towing, and/or high outside temperatures, the fan speed increases as the clutch more fully engages, so you may hear an increase in fan noise. This is normal and should not be mistaken as the transmission slipping or making extra shifts. It is merely the cooling system functioning properly. The fan will slow down when additional cooling is not required and the clutch partially disengages.