I just bought a 2006 2,5TDI R5 two days ago. I noticed that the water temperature is low. City driving it is about 60-65 degrees. When i cruise on the highway it does come up to almost 90 degrees after a long time, but drops straight down again when driving in town. Is that normal operating temperature for the 2,5 tdi? I am used to the water temp goes to 90 degrees and stay there..