I remember when I was 17 years old and my friends brother bought B7 like this one. When he gave us a ride I though it's the best car ever. Of course I didn't know any better back then. And I remember that I thought it's extremely powerful :D.
Calorstat or Temp sensor h.s got it on my 420 000KM A4 B6 1.9 tdi. Know problem on 1.9 / 2.5 TDI i never get this prob on my 3.0 TDI now they are both at 90 all time.