i have a 02 vectra. sometimes i think the tempreture gauge is giving me false readings. the gauge goes up into the red and if i turn the ignition off and the back on it returns to normal. i have had the cam belt and water pump changed. it has had a new thermostat .does anybody have any ideas. the fan doesnt come on wen it does this but other wise works. thank you

john g, July 2013

I have an 04 plate 3.0 v6 diesel doing exactly the same, ive changed the cam belt, thermo stat and water pump, seems to be ok at low speeds!! it does build a lot of pressure in the water , I have no idea aprt from change the radiator what else to do?? PLEASE HELP ME!!!!!

Chris V, August 2013

could be the temp sensor in the rad or water pump housing,or could be the voltage regulator for the gauge

mm, July 2013

it may be worthwhile getting the motor onto a computer to look at live data regarding your temp.readings

cdc, July 2013