Originally Posted by
jdance
Its the thermostat for sure. Hot day (if we ever get one) - stop at traffic lights - needle starts moving up the gauge - start moving again - needle falls. Classic symptoms. Very unlikely to be the sensor - they rarely fail - if you are concerned put a multi-meter across the sensor and see if the resistance changes!
Brilliant, thanks. Not too concerned about it being the sensor, just thought I'd exhaust all possibilities.
Out of interest, where should the needle on the oil temp gauge usually sit? Mine barely gets above cold most of the time, but I assumed the oil wouldn't get too hot with average day to day driving. Someone told me that the oil temp gauge is a 'guesstimation' based off the water temp?