01 Navigator shows hot

[oldgater01]

My 01 Navigater will show hot suddenly when I get up to about 50MPH. I can turn off the key and then immediately restart and the gauge shows normal. I have flushed radiator and engine, replaced radiator cap, replaced temperature sensor. The water pump is fine. The radiator shop says the radiator is OK. Any suggestions? Has anyone had this radiator partially collapse inside?

[Fordace]

can't find any concerns on this, maybe you need to burp the cooling system again? That's if you recently had it flushed. You might have an air pocket which can be dangerous for aluminum heads