worst case scenario, head gasket blown, very common after an overheat. First check the thermostat is opening correctly, replace if any doubt. next is the water pump, sounds like the impellor has gone, isn't shifting water round the system. whoever does the work, i would recommend changing the timing belt, tensioners, and idlers at the same time, unless you know that they are well within date. This will probably cost a bit.
Lee Nias, April 2008
