So 8 months ago i had my head gasket replaced, 2 days later i notice steam coming from under the bonnet, turns out it was the thermostat, everything was fine until today, steam once again coming from under the bonnet , cooolant tank virtually empty...so, in the past 8 months its had a brand new head gasket, brand new thermostat, brand new coolant tank cap...

Any ideas what it could be this time???

 

can't rule out head gasket. depends how well it was done. why did it fail before? was the head skimmed before refitting -this is making the underside of the head (where it presses on the gasket) dead flat.  Because one of the reasons a gasket fails is due to the head warping and if you put a new gasket on a warped head it is not going to last . also head bolts need torquing to correct setting in the correct order, and usually using brand new bolts. 

sadly it is not that rare for head gaskets to fail again, you sometimes see cars advertised where it says head gasket just done suggesting that is a positive, to me it's a negative.

But it might not be that

If it's been steaming off you might've blown the head gasket again. Could've caused a cylinder (or a few) to warp and it's started leaking.

the work done is still under warranty so its upto the garage to sort it, thats something at least

Turns out its the Thermostat housing x