Ford Fiesta - Half of expension tank cap stuck in tank

[Targarama]

Removed the expansion tank cap on lady Targ's 2010 Fiesta and the cap came apart with half of it stuck in place in the tank. I managed to rotate the remaining part a bit with some pliers but it won't come out (snapped a few bits off in the process). Any suggestions? I bought a new cap and the piece that is stuck in there is just held in with a rubber 'o' ring type seal - the cap part is what screws down on the thread. The pressure valve is still fine, put the cap back on and drives with no issues, its just that the expansion water has dropped a smidge and I'd like to fix this before I 'have to' IYSWIM.

[Targarama]

WinstonWolf said:

I'd drill a small indent in the side of the remains of the cap then use a metal bar to rotate it. Just make sure you don't break through...

Thanks, I'll have a look at doing this.

[Targarama]

Sorted, thanks for the hints chaps. Put a screw through the side and got some mole grips on it, came out after a few twists to loosen the seal. Crap design.

I think the open when hot was a joke.