I have a temperature problem on my Astra G 51 plate 1.8 Sri. The garage have looked at it twice, but can't isolate the problem. They think its electrical and don't do electrics .
The coolant system is fine, no leaks and had a new water pump a year ago, so no problem there.
What happens is no matter what the weather, after about 5 mins of driving the temperature guage goes upto the 100 mark and is usually just over middle mark.
In hotter weather it goes nearly to the red and in both cases both engine fans turn on and stay on whilst driving(which is very noisey I must say on the Sri).
When the engine is turned off just one of the fans stays on for about a minute then turns off. The engine is not overheating in any way and emissions levels are fine.
I have read a few posts similar to this and some suggest it could be a problem with the thermostat or maybe the temperature guage. Not sure how you could diagnose, which one it is.
Any ideas please?