Thank you for your comments about my problem with my 1996 for f150, I checked to see if the fan clutch was able to move, it is very secure, there has been a new serpenteen belt put on. So still don't know what is causing the noise, happened one day after it was worked on.

truck is making a noise like some thing is hitting the fan or fan is hitting something this
happened after serpenteen belt was put on, a new water pump, and a throttle control
sensor, because my truck was accelerating with out my foot on pedal.  My truck was
running fine, I was told it had a slight water pump leak, so decided to replace it
because was going to go across country, didn't do that yet though.  Took this back to
the original mechanic, left it sit over night(it only seems to sound worse  when started
up, has to sit at least 3 hours.  I can hear it pecking at drive up also.  Mechanic told be
it was only a dry belt, but it was a new belt, he did replace the serpenteen belt, didn't
help the noise it also doesn't want to accelerate at the stop sign when I go to take off,
noise seems also to be worse when cold but does it when warm as well.  Thank you for
your time, and any help figuring this out.  Had my  truck to several mechanics
everyone says something different and no one is right,. they just want to keep charging
me money.