Hi

Yesterday while sitting in traffic smoke started coming out from under the bonnet so i pulled over and looked and the coolant tank was empty. So i filled it up with water and nothing came out. so i drove it about 15 miles and then checked and it was back down to half. Filled it up to the max level and drove about 25 miles home and no coolant leaked out, anybody have any ideas what is wrong?

TA

It's probably either a duff thermostat or an airlock in the coolant pipes.

A friend had the same problem after replacing both of those things he found that he had a split in the water bottle that opened more as the engine warmed up but would close as it cooled down arnt cars very strange things

Similar thing happened to my old Punto (being a Punto I assumed the headgasket had popped lol) but just refilled and off I went. It was probably an air lock in the system somewhere, my temperature gauge went up and like you lifted the bonnet and was greeted with smoke. Was horrible as I was quite some distance from home, like Lee said cars are funny things and things like this happen sometimes. You should be okay but if it happens again check all hoses for leaks/splits and replace the thermostat as Clive suggested. :)