My 2002 1.9TDi Galaxy has just started to do this. Overheating with stop message on the dash, temp going 130 degrees. When you say corrosion over 2 electrodes where are they located on the expnsion tank? I really cant afford to go to the fraud dealers anymore! I am hoping this is the cause of the overheating instead of the expensive water pump/cambelt change.... Great Forum, Great Guys & Gals wish FRAUD DEALERS visit the forum Kind Regards Shahed My 2001 1.9TDI has had similar problem but only when travelling under load and have lost coolant as well. I have had new thermostat and checked for water in engine but no signs. Is it possible that it is a problem with water expansian tank allowing water to escape or sensor problem not activating fans ? any ideas ? Chris