The odd thing here is that the car's tendency to run hotter in cold
ambient
temps probably means the problem with the clutch fan is related to the
'sensor' (not sure what to call it) not being able to cope with cold,
not
hot.
That screams thermostat (or eroded thermostat housing) to me, not fan
clutch.
Not all brand-new thermostats are good ones. When you feel the radiator
immediately behind the fan, is it hot or cold? When the SDL's radiator
was clogged that area was cold, so of course the fan clutch wouldn't
(and shouldn't, and wouldn't have done any good if it had) engage.
-- Jim