I've got an R reg Corsa, after 5-10 mins of normal driving the engine temperature rises to 98 degrees, it then falls back down really quickly to about 92, It then will run on just over 95 for the rest of the time. Until I stop at traffic lights etc when it rises to 100, and then fan kicks in.
It never used to do this, is something wrong?
The water level is fine though it looks a bit brown!
I agree with tellboy - your thermostsat is stickinga bit - if your car has a timing belt it is located behind it - but you do need to change it as it will only get worse in my experience.