The coolant temperature in my car has always been around 70 -75. It suddenly moved to 90 last week on a long journey (but has not yet gone above this level). At the same time the engine started to make a noise - almost as if it was straining when in 3rd or 4th gear at speeds of over 30mph. I am not sure if the two are connected. I am taking the car to a garage this week but wondered if anyone has any ideas about things to check.