2007 Chrysler Aspen Owner's Manual - Page 372

372 MAINTAINING YOUR VEHICLE Drive Belts - Check Condition and Tension Belt tension is controlled by means of an automatic tensioner. No belt tension adjustments are required. However, belt and belt tensioner condition should be inspected at the specified intervals, and replaced if required. See your authorized dealer for service. At the mileage indicated in the maintenance schedule, all belts and tensioner should be checked for condition. Improper belt tension can cause belt slippage and failure. Belts should be inspected for evidence of cuts, cracks, glazing, or frayed cords and replaced if there is indication of damage which could result in belt failure. Low generator belt tension can cause battery failure. Also check belt routing to make sure there is no interference between the belts and other engine components. Spark Plugs Spark plugs must fire properly to assure proper engine performance and emission control. The plugs installed in your vehicle should operate satisfactorily in normal service for the mileage indicated in the Maintenance Chart. New plugs should be installed at this mileage. The entire set should be replaced if there is any malfunction due to a faulty spark plug. Check the Vehicle Emissions Control Information label for the proper type of spark plug for your vehicle. CAUTION! When replacing plugs, do not overtighten. You could damage them and cause them to leak.