2002 Lincoln LS V8 overheating problem

Hey I have a 2002 Lincoln LS V8. The
problem that I'm having is that the car is
overheating I just purchased a car used and
I have done the following things to see if I
can get it to stop overheating. I have flush
the engine water radiator Peaks radiator
flush I've also took out the thermostat why
was Flushing the radiator and Reservoir
what a cooling system as a whole and the
car still was overheat the only time it
overheats is when I drive more than an hour
I would like to know what it could possibly
be the car is not smoke coming from the
tailpipe and I haven't noticed eating water
pump issues the cooling fan the seem like it
running a little slow but I'm not sure because
I never owned only can before and don't
know if the fan is supposed to move it the
rate that is moving the water pump does
seem like it's pumping water through the
system but it seems that the recovery tank
is not circulate in the water to the radiator
and when it overheats all I hear is the
bubbling sound inside a recovery tank so
what other problem could it be for as this
matter I really don't have the money to do a
major overhaul on this vehicle due to some
personal and family issues that I'm currently
going through so what else could it be I did
take it to a mechanic and he put the bars
stop leak in it and that didn't seem like it
work the sari flush the system out again to
get all that stuff from bars out the system
and see if I can get it out so what else could
it be to let his car overheat it don't seem I
don't see any leaks when it possibly could
cause everything so compact in the engine
area so what else could it be like I said the
recovery tank doesn't seems like it's
circulate in the water through the system fill
it up a couple times and left it running and it
just seemed like it wasn't pumping through
the system correctly so like I said the portal
pump is working but what else could it be to
make car overheat please reply soon thank
you