1994 Chevrolet S10 Pickup Owner's Manual - Page 201

7. By this time thecoolant level inside thefiller neck may be lower. If the level is lower, add more the proper mix through the filler neck until of the level reachesthe base of the filler neck. 8. Then replace the pressure cap. P At any time during this procedure if coolant begins to flow outof the filler neck, reinstall the pressure cap. Be sure the arrows on pressure cap line up like this. ' Engine Fan Noise This vehicle has a clutched engine cooling fan. When clutch is engaged, the the fan spins faster to provide more air cool the engine. In most every day to driving conditions the clutch not engaged. This improves fuel economy is and reducesfan noise. Under heavy vehicle loading, trailer towing and/or high outside temperatures, thefan speed increases when clutch engages. the So you may hear an increase in noise. This is normal and should not be fan mistaken as the transmission slipping making extra shifts. It is merely the or cooling system functioning properly. fan will slow down when The additional coolingis not required and the clutch disengages. You may also hear this fan noise when youstart the engine. It will go away as thefan clutch disengages. 5-19