Hi everyone,
my 92 prelude temp gauge will, once in a while, start to move up, and continue all the way to the top (overheat). It happens usually after a period of idling, but not everytime. It doesnt seem to matter how hard i drive it, just sometimes at idle (and today in 2nd gear) it decides to try and overheat.

I'm not losing coolant, the fan comes on at higher temps, i changed the thermostat already. I can drive it hard on the highway for 20 miles without a peep, so i assumed that the radiator must be fine. Anyone have any ideas before i think about messing with my water pump (which obviously works most of the time)?

Could it be trapped vapor?

Thanks.

 

probably an air bubble or try changing your cap