2010 Hummer H3T Owner's Manual - Page 290

10-24 Vehicle Care Engine Fan This 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 clutch is not engaged. This improves fuel economy and reduces fan noise. Under heavy vehicle loading, trailer towing and/or high outside temperatures, the fan speed increases when the clutch 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 disengages. You may also hear this fan noise when you start the engine. It will go away as the fan clutch disengages. Power Steering Fluid How to Check Power Steering Fluid 1. Turn the key off and let the engine compartment cool down. 2. Wipe the cap and the top of the reservoir clean. See Engine Compartment Overview on page 10‑6 for reservoir location. 3. Unscrew the cap and wipe the dipstick with a clean rag. 4. Replace the cap and completely tighten it. 5. Then remove the cap again and look at the fluid level on the dipstick. The level should be between the ADD and FULL marks. If necessary, add only enough fluid to bring the level up to the proper range. When to Check Power Steering Fluid It is not necessary to regularly check power steering fluid unless a leak in the system is suspected or an unusual noise is heard. A fluid loss in this system could indicate a problem. Have the system inspected and repaired.