2012 GMC Sierra Owner's Manual - Page 411

Vehicle Care loading, trailer towing, and/or high outside temperatures, the fan speed increases as the clutch more fully engages, so an increase in fan noise may be heard. 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. This fan noise may also be heard when starting the engine. It will go away as the fan clutch partially disengages. If the vehicle has electric cooling fans, the fans may be heard spinning at low speed during most everyday driving. The fans may turn off if no cooling is required. Under heavy vehicle loading, trailer towing, high outside temperatures, or operation of the air conditioning system, the fans may change to high speed and an increase in fan noise may be heard. This is normal and indicates that the cooling system is functioning properly. The fans will change to low speed when additional cooling is no longer required. 10-25 How to Check Power Steering Fluid Notice: Extremely small amounts of contamination can cause steering system damage and cause it to not work properly. Do not allow contaminants to contact the fluid side of the reservoir cap/ dipstick or to enter the reservoir. To check the power steering fluid: 1. Turn the key off and let the engine compartment cool down. Power Steering Fluid See Engine Compartment Overview on page 10‑6 for reservoir location. 2. Wipe the cap and the top of the reservoir clean. 3. Unscrew the cap and wipe the dipstick with a clean rag. 4. Replace the cap and completely tighten it. 5. Remove the cap again and look at the fluid level on the dipstick. The level should be at the FULL COLD mark. If necessary, add only enough fluid to bring the level up to the mark. When to Check Power Steering Fluid It is not necessary to regularly check power steering fluid unless there is a leak suspected in the system or an unusual noise is heard. A fluid loss in this system could indicate a problem. Have the system inspected and repaired.