after hearing from David B... we set about for  Sunday morning rehash  of
our thermostat puzzlement... It is our least favorite task on the waterbox
cooling system as this is the last place where antifreeze gets to run
loose...

 We installed our purging,drain, and fill valve in the lowest hose ....
under the spare tire trap door... it can be reached without dropping the
tire door... that happens to be the return line from the radiator to the
thermostat.... we have been filling the system with a non automotive device
stolen from the mechanical contracting trade called a force pump...  it is a
low volume manually operated pump used to put chemicals into pressurized
systems... with this, we can add coolant to the system while the engine is
hot with little risk... the down side of this, is that the pump can produce
significant pressures...  in excess of 100 psi ... it does not have to do
that ...it just has that capacity... there is some possibility that in our
enthusiasm  we over did the pumping and somehow toasted the thermostats...
We are not sure how sturdy they are as we have not jumped up and down on any
as of yet ... a shortcoming of information which we intend to rectify
shortly.... we did not blow the pump seal... all in all thermostats or no we
are still pretty happy with the results of the system so far