A4 tdi awx engine was losing water for sometime now,drove perfect apart from water dissapearing........anyway it was driven down the motorway a few days ago and after around 50 miles.....coolant 'low' light came on,pulled in the services(temp now on the red!) waited and then put water in it,car lost power and smokes that bad that i had to call rac out as it was not fit to be driven as the smoke was very bad! mix of whitish/blueish smoke......any idea?