[inafogg]

I still think there is either a block somewhere in the system or a innoperable water pump. The fluid is not moving in the system causing the temperature to fluctuate with the movement of the car until the engine heats the fluid too much as movement through traffic no longer cools the engine enough. Is there a way to check if the pump is adequately moving fluid?

Thanks[/quote]

the only way i can think of is to open the bleeder valve by thermo housing.with engine running you should have a pretty strong flow.
there should be another bleeder around the water pump.i'm curious
as to what the dealer has to say,something like there was air trapped
in the system.

has anyone verified that the radiator cap is ok. as mentioned before if
its not holding the system pressure,you may be loosing coolant out of the top of resivour and may not see it.this would take awhile & not the reason its overheating now but it could of been the reason for the original trouble.
while at the dealer ask them to check the cap!!and watch them do it