or does the temp gauge just rise up because of the steam or coolant? Reason why im asking is because i was driving and my temp gauge went all the way to the red and then dipped down half way did this about 3 times .. so when it hit the red was the actual engine block temp 260 or did it give it a false reading because of the air pocket? because it heated up so fast then cooled down just as fast? thanks!

 

Air pockets give false readings.