Driving along and my temperature gauge rises to hot. Sometimes it the temp. will drop on the gauge, some times it won't.
My temp. gauge climbs to HOT; not sure what to replace - Thermostat or Fan relay on 2002 Honda Civic Si
does the fan work? if fan works relay is good
I would try changing the t stat if that doesnt work then I would check the head gasket
Have you checked the coolant level (cold), in both rad. and reservoir?