I lost five of six bolts on water pump pulley and in turn the serpentine belt was cut and down the truck went............I'm wondering what caused the bolts to loosen and fall out of pulley. I'm thinking the balancer on fan or what......no water pump problems that I can see .....I need some help !!! 2000 model 5.9 diesel automatic 4 wd.

 

WTF are you talking about?

there are only 2 bolts that hold the water pump on, and the pulley is part of the pump and gets replaced with the pump. it's sold as a complete part.

 

my pulley not slick has the grooves for the belt, located directly behind the fan with 6 bolts 1/4" x 20 fine thread

 

That is the fan pulley, and has nothing to do with the water pump. The viscous clutch attaches to this fan this way. Not sure why it would loosen off, but I suggest a new viscous clutch and hardware. Install with new hardware, red loctite, and torque to spec. It will likely never happen again.

 

thanks guys, ..............I did replace bolts and locktite and lock washers. The fan is not freewheeling when I cut the engine off everything seems normal but I 'm not sure about clutch if it vibrated enough to shake the bolts out......it cost me two nites in motel and a haul bill to get going. Expensive serpentine belt. .......... thx for all your imput