Join Date: Jun 2002
Location: USA & Singapore
Ferrari Life Posts: 5,509
Just reread what I posted and realized I misspelled a word. I meant that "I wouldn't completely trust the gauge." I gather you realised my error.
Did you happen to notice if the oil temperature was doing the same thing?
I assume you have already rechecked all the fluid levels to make sure none of them are low.
Just a theory, It could be that the thermostat was partially closed due to the higher coolant velocity at the highway speeds, trying to prevent the engine from being overcooled, and then when you brought it into town and the speed of the engine and the speed of the coolant decreased, the thermostat stuck for a minute giving you that quick rise in temperature. When the thermostat became unstuck and went fully open, the temperature quickly went back down.
Keep an eye on it. I wouldn't really become overly concerned until it starts climbing up over 110.
'79 308 GTS, '82 Jeep CJ7 Jamboree
"Time is what prevents everything from happening all at once."