F 150 4WD V8-5.4L Flex Fuel (2008)
automatic belt tensioner maintains correct belt tension and compensates for component wear and changes in system load. System load changes can be
caused by the A/C compressor clutch engaging and disengaging, or demand changes on other systems powered by the accessory drive belt. To maintain
correct operation of this stem, it is critical that the correct length drive belt be installed. The pulleys must also be correctly aligned and kept clean.
