had a water pump, serpintine belt, throttle sensor put on 1996 ford f150 in august the mechanic told me it was a dry belt my truck sounds like something is hitting the fan mechanic had left the shroad

had water pump, serpentine belt, throttle sensor put on aug 2014 ford f150 1996 truck
immediately sounded like something hitting the fan or fan hitting something, mechanic
said it was a dry belt, so I made him put a new serpentine belt and tensioner on, didn't
solve the problem.  mechanic had left the fan shroad cover loose so another mechanic
tightened that, he thought that might be the problem no such luck.  I especially notice
the noise when starting it up, or after it has sat for 3 hours.  I didn't have this problem
till the water pump and the other things mentioned above were worked on truck was
running smooth.  Please help this is my only means of transportation, I am a disabled
senior, not one can figure out what this can be or what this mechanic may have done
to it.  None of them seem like they know what they are doing, each one says
something different.