1998 Chevrolet Astro Owner's Manual - Page 244

Engine Fan Noise This vehicle has a clutched engine cooling fan. When the clutch isengaged, the fan spins faster to provide more air to cool theengine. In most everyday driving conditions, the clutch is notfully engaged. This improves fuel economy and reduces fan noise. Under heavy vehicle loading, trailer towing andor high outside temperatures, the fan speed increases when the clutch engages. So you may hear an increase infan noise. This is normal and should not be mistaken the as transmission slipping or making extra shifts. It is merely the cooling system functioning properly. The fan will slow down when additionalcooling is not required and the clutch disengages. You may also hear this fan noise when you start the engine. It will go awayas the fan clutch disengages. If a Tire Goes Flat It's unusual for a tire to "blow out" while you're driving, especially if you maintain your tires properly. If air goes out of a tire, it's much more likely to out slowly. leak But if you should ever have a "blowout," here are a few tips about what to expect and what do: to If a front tire fails, theflat tire will create a drag that pulls the vehicle toward that side. Take your off the foot accelerator pedal and grip the steering wheel firmly. Steer to maintain lane position, and then gently brake to a stop well out of the traffic lane. A rear blowout, particularly ona curve, acts much like a skid and may require the same correction you'd use in a skid. In any rear blowout, remove your foot from the accelerator pedal. Get the vehicle under control by steering the way you want the vehicle to go. It may be very bumpy and noisy, but you can still steer. Gently brake to a stop -- well off the road if possible. If a tire goes flat, the next part shows how to use your jacking equipment to change a flat tire safely. 5-22