UK Car Repair: water thermostat, upper radiator hose, temp gauge

Question
QUESTION: i have a r req vectra i have notice the temp gauge never seems to rise much  ,,allthough the heater seems ok ..i think the water thesmostat might have stuck open..i have change these on other cars .but i cant seem to find where it is on my vectra can you advise
thanks
stuart       1.6     r req 4 door petrol

ANSWER: Did you get my previous response?

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QUESTION: hi again i did not get your 1st responce
thanks
stuart

Answer
First, you should check the temperature at the upper radiator hose, a simple thermostat taped on should be sufficient unless you have access to a pyrometer. Does the electric fan ever come on? if not, try to make it do so by blocking off the radiator and watching to see if the gauge reacts. It may just be a gauge problem.