1995 GMC Jimmy Owner's Manual - Page 222

6. Start theengine and let it run until you can feel the upper radiator hose getting hot. Watch out for the engine fan. 7. By this time the coolant level inside the filler neck may be lower. If the level is lower, add more the proper mix through the filler neck until of the level reaches the base of the neck. filler 8. Then replace the pressure cap. At any time during this procedure if coolant begins to flow out of the filler neck, reinstall the pressure cap. Be sure the arrows on the pressure cap line up like this. Engine Fan Noise This vehicle has a clutched engine cooling fan. When the clutch isengaged, the fan spins faster to provide more air cool the engine. In most every day to driving conditions the clutch is notengaged. 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 slippingor making extra shifts. It is merely the cooling system functioning properly. The fan slow down when will additional cooling is not required and the clutch disengages. You may also hear this fan noise when you start the engine. It willgo away as the fan clutch disengages. 5-20