Quick check. Next time it gets up by the red, pull over a pop the hold. Usually if an engine is really overheated, you can tell. Things under the hood are way hotter than usual. Look at the overflow tank - is it overflowing?

The system is designed to run at about 14psi above atmospheric pressure. This raises the boiling point of the coolant to around 250F degrees. If the overflow tank/cap are failing - pressure is low, coolant can boil. May have a weird effect on temp gauge reading.

Also, try the karate jab system - detailed in another earlier of my posts.

Good Luck,

Bob

:>)