Everything, head gasket problems mainly.
Engine is a rubbish design. Just asking for problems - diesel with aluminium block and wet liners causing head gasket problems.
I have a AX 1.4 TRD and I have the same problem with the head.
I'm from Italy. I have bought a car (if we can say it's a car) like this in the 96's and I have changed its engine two times. Actually it's seem to require a new engine every 60.000 Km; about one time every three years.
Nowadays I use it just for carrying my children to school and when I return at home the temtperature's light has became red.
I think that an engine like this should have been withdrew from the marked at the beginning.